System and method for autonomously removing fasteners embedded in wood products

ABSTRACT

A method includes: receiving a recycled wood workpiece populated with a set of metal fasteners; accessing an internal imaging scan; detecting the set of metal fasteners embedded in the recycled wood workpiece based on internal features detected in the internal imaging scan; for each metal fastener in the set of metal fasteners, extracting an initial position and an initial orientation of the metal fastener from the internal imaging scan; generating a virtual model of the recycled wood workpiece based on the internal imaging scan; accessing an image captured by an optical sensor; detecting a first metal fastener in the recycled wood workpiece; deriving a first position and a first orientation of the first metal fastener; and, in response to identifying the first metal fastener analogous to an initial metal fastener in the virtual model, isolating the first metal fastener in the virtual model and generating a fastener removal schedule.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/316,933, filed on 4 Mar. 2022, 63/316,935, filed on 4 Mar. 2022, and63/419,244, filed on 25 Oct. 2022, each of which is incorporated in itsentirety by this reference.

TECHNICAL FIELD

This invention relates generally to the field of material recycling andmore specifically to a new and useful system for autonomously removingfasteners embedded in wood products in the field of material recycling.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic representation of a system;

FIG. 2 is a flowchart representation of a method;

FIGS. 3A and 3B are schematic representations of one variation of thesystem;

FIGS. 4A and 4B are schematic representations of one variation of thesystem;

FIG. 5 is a flowchart representation of one variation of the method;

FIGS. 6A and 6B are schematic representations of one variation of thesystem;

FIGS. 7A and 7B are schematic representations of one variation of thesystem; and

FIGS. 8A and 8B are flowchart representations of one variation of themethod.

DESCRIPTION OF THE EMBODIMENTS

The following description of embodiments of the invention is notintended to limit the invention to these embodiments but rather toenable a person skilled in the art to make and use this invention.Variations, configurations, implementations, example implementations,and examples described herein are optional and are not exclusive to thevariations, configurations, implementations, example implementations,and examples they describe. The invention described herein can includeany and all permutations of these variations, configurations,implementations, example implementations, and examples.

1. System

As shown in FIGS. 1, 3A, 3B, 4A, 4B, 6A, 6B, 7A, and 7B, a system 100for autonomously removing fasteners embedded in a recycled woodworkpiece 115 includes: an X-ray scan module 112; a chassis 102; aconveyor 105; an optical sensor 110 (e.g., 3D depth camera); a fastenerextractor module (e.g., a non-threaded fastener extractor module 120, athreaded fastener extractor module 130); a metal scan module 150; and aprimary controller 160.

The chassis 102 defines a scan volume and a work volume 109. Theconveyor 105 runs from an entry of the chassis 102 to an exit of thechassis 102 and is configured to receive a recycled wood workpiece 115populated with metal fasteners. The X-ray scan module 112 is supportedby and arranged within a threshold distance of the entry of the chassis102 and includes an X-ray sensor facing the scan volume. The opticalsensor 110 faces the work volume 109.

The fastener extractor module includes: a stage supported by the chassis102; an extractor end effector supported and manipulated on the chassis102 via the stage and configured to engage and retain metal fastenersfrom a section of the recycled wood workpiece 115 occupying the workvolume 109; and a controller (e.g., local controller 170). Thecontroller (e.g., local controller 170) is configured to: access aseries of X-ray scans of the recycled wood workpiece 115 within the scanvolume captured by the X-ray sensor; compile the series of X-ray scansinto a virtual model of the recycled wood workpiece 115 annotated withpositions, orientations, and fastener types of metal fasteners extractedfrom the series of X-ray scans; and access an image of the work volume109 captured by the optical sensor 110. Based on features detected inthe image, the controller (e.g., local controller 170) is furtherconfigured to detect a first metal fastener in the section of therecycled wood workpiece 115 occupying the work volume 109 and extract aposition and orientation of the first metal fastener. The controller(e.g., local controller 170) is also configured to: map the first metalfastener in the section of the recycled wood workpiece 115 to thevirtual model based on the position and orientation of the first metalfastener; and prescribe a fastener removal schedule defining a tool pathfor the extractor end effector to extract the first metal fastener fromthe section of the recycled wood workpiece 115.

The metal scan module 150 is arranged on the chassis 102 within thethreshold distance of the exit of the chassis 102 and includes a metalline scanner facing the scan volume and configured to detect metalfasteners within the recycled wood workpiece 115. The controller isfurther configured to: access a first metal scan of the recycled woodworkpiece 115 within the scan volume, captured by the metal linescanner; trigger the conveyor 105 to drive the recycled wood workpiece115 to a recycled wood workpiece 115 pallet; and reset the conveyor 105to an initial position at the entry of the chassis 102, in response toabsence of metal fasteners detected in the first metal scan of therecycled wood workpiece 115.

One variation of the system 100 includes: a chassis 102 defining a workvolume 109; a conveyor 105 configured to receive the recycled woodworkpiece populated with metal fasteners and configured to constrain asection of the recycled wood workpiece 115 within the work volume 109;an optical sensor 110 facing the work volume 109; a non-threadedfastener extractor module; and a controller (e.g., local controller170). The non-threaded fastener extractor module 120 includes a stage121 supported by the chassis 102 and a non-threaded fastener endeffector 122. The non-threaded fastener end effector 122 is supportedand manipulated on the chassis 102 via the stage 121 and includes: a setof jaws 128 configured to engage and retain metal fasteners from thesection of the recycled wood workpiece 115; and a jaw actuator 125configured to actuate the set of jaws 128. The controller is configuredto: access an image of the work volume 109 captured by the opticalsensor 110; based on a set of features detected in the image, detect afirst fastener in the section of the recycled wood workpiece 115occupying the work volume 109 and derive a first position and a firstorientation of the first fastener in the work volume 109; define a firsttarget engagement position of the non-threaded fastener end effector122, to engage the first fastener, based on the first position and thefirst orientation of the first fastener within the work volume 109;trigger the stage to drive the non-threaded fastener end effector 122 tothe first target engagement position; trigger the jaw actuator 125 todrive the set of jaws 128 to engage the first fastener in the section ofthe recycled wood workpiece 115; and trigger the stage 121 to retractthe non-threaded fastener end effector 122 from the first targetengagement position to extract the first fastener from the recycled woodworkpiece 115.

2. Applications

Generally, the system 100 is configured to recycle used lumber (e.g.,construction wood products) populated with metallic objects by:receiving an inbound recycled wood workpiece 115; scanning the inboundrecycled wood workpiece 115 with a set of internal imaging, depth,and/or color sensors; implementing computer vision techniques to detectand distinguish threaded fasteners (e.g., screws) and non-threadedfasteners (e.g., straight nails, bent nails, staples) in the recycledwood workpiece 115; and then selectively manipulating a set of threadedfastener and non-threaded fastener extractor modules 120 to autonomouslyengage, retain, and remove these fasteners.

For example, the system 100 can process recycled wood workpieces 115(e.g., wood products) including recycled wood workpieces 115, joists,beams, columns, and plywood sheet goods to: characterize recyclabilityqualities of sections of these wood products; mark or resect sections ofthese wood products for discard based on embedded metal, structuraldamage, or low recyclability quality within these sections; and detectand remove threaded fasteners (e.g., screws), non-threaded fasteners(e.g., straight nails, bent nails, staples, retainer nails), and othermetallic objects embedded and/or extending above the sections of theserecycled wood workpieces 115 characterized by sufficient recyclabilityqualities.

Furthermore, the system 100 can receive a recycled wood workpiece in ascan volume of an X-ray scan module. Then the primary controller 160can: access internal imaging data captured by the X-ray scan module 112;detect internal features representing metallic objects (e.g., possiblemetal fasteners) in these internal imaging data; extract positionsorientations of these internal features; identify a fastener type ofeach internal feature; and compile these internal imaging data into athree-dimensional representation (or “virtual model”) of the recycledwood workpiece 115 annotated with positions, orientations, and fastenertypes (e.g., non-threaded, threaded, nail, staple, screw). The system100 can then receive a recycled wood workpiece 115 in a work volume 109of a fastener extractor module (e.g., non-threaded fastener extractormodule 120, threaded fastener extractor module 130). The primarycontroller 160 can then: access optical scan data captured by an opticalsensor 110 and/or set of optical sensors 110 facing the work volume 109;detect external features embedded within and/or extending above surfacesof the recycled wood workpiece 115 based on these optical scan data; mapeach external feature to a corresponding internal feature in the virtualmodel; identify each external feature and internal feature pair as ametal fastener; generate a fastener removal schedule to remove eachfastener from the recycled wood workpiece 115; and transmit eachfastener removal schedule to a local controller 170 of a correspondingfastener extractor module (e.g., non-threaded fastener extractor module120, threaded fastener extractor module 130) to execute each fastenerremoval cycle.

2.1 Non-Threaded Fastener Extractor Module

Furthermore, the system 100 can also include a set of non-threadedfastener extractor modules 120. Each non-threaded fastener extractormodule 120 includes: a stage (e.g., multi-axis stage); a non-threadedfastener end effector 122; a set of module actuators; and a localcontroller 170. The non-threaded fastener end effector 122 includes: abearing plate 123; a vertical stage 124 arranged on the multi-axis stage121 and is configured to support the bearing plate 123, advance thebearing plate 123 toward a non-threaded fastener in a recycled woodworkpiece 115 occupying the work volume 109, and retract the bearingplate 123 to withdraw the non-threaded fastener from the recycled woodworkpiece 115; and a jaw actuator 125 arranged on the vertical stage124, coupled to a set of jaws 128 and configured to close the set ofjaws 128 to engage the set of jaws 128 against a non-threaded fastenerand to open the set of jaws 128 to release the non-threaded fastenerfrom the set of jaws 128.

The system 100 can execute a non-threaded fastener removal cycle inconjunction with each non-threaded fastener extractor module 120. Forexample, the primary controller 160 can further characterize a qualityof the recycled wood workpiece 115 based on internal features within thevirtual model and identify each non-threaded fastener as a nail and/or astaple (e.g., straight nail, bent nail) and a characteristic of the nailand/or staple (e.g., superficial, subsurface, flush, normal, non-normalrelative a surface of the recycled wood workpiece 115, dimension). Thelocal controller 170 can then execute a non-threaded fastener removalschedule by: autonomously navigating the non-threaded fastener endeffector 122 to a target engagement position, via the stage 121 (e.g.,multi-axis stage), and to a target jaw position, via the yaw actuator127 above the nail and/or staple in the recycled wood workpiece 115; andtrigger the jaw actuator 125 to close the set of jaws 128 to engage theset of jaws 128 against the nail and/or staple with a target clampingforce. Upon completion of the non-threaded fastener removal cycle, thelocal controller 170 can trigger the vertical stage 124 to retract thebearing plate 123 to extract the nail and/or staple from the recycledwood workpiece 115 and trigger the jaw actuator 125 to open the set ofjaws 128 to release the non-threaded fastener from the set of jaws 128into a fastener container 145 (e.g., waste bin).

The local controller 170 can then verify removal of the non-threadedfastener from the recycled wood workpiece 115. If the non-threadedfastener crosses a beam sensor in the fastener container 145, the localcontroller 170 can confirm removal of the non-threaded fastener at theend of the non-threaded fastener removal cycle. If the non-threadedfastener does not cross the beam sensor in the fastener container 145,the local controller 170 can flag the non-threaded fastener as a failureat the end of the non-threaded fastener removal cycle. Alternatively, ifthe offset distance of the set of jaws 128 falls below an offsetdistance threshold, the local controller 170 can flag the non-threadedfastener as a failure at the end of the non-threaded fastener removalcycle.

Additionally, the system 100 can implement computer vision techniques todetect and distinguish removal failures (e.g., slipped, snipped, broken,missed) for non-threaded fasteners. The system 100 can then update afastener removal schedule to reduce failure of future fasteners withanalogous characteristics such as fastener type, location relative therecycled wood workpiece 115 (e.g., subsurface, superficial, flush,normal, non-normal relative the surface of the recycled wood workpiece115), and/or fastener size.

2.2 Threaded Fastener Extractor Module

The system 100 can also include a set of threaded fastener extractormodules 130. Each threaded fastener extractor module 130 includes: astage 131 (e.g., a multi-axis stage); threaded fastener end effector132; a set of module actuators; and a local controller 170. Themulti-axis stage is arranged in a work volume 109 defined by the chassis102 and faces the work volume 109. The threaded fastener end effector132 is supported by the multi-axis stage and includes: a housing 134; aram 136 arranged and configured to rotate in the housing 134; a set ofjaws arranged on a distal end of the ram 136; a jaw actuator configuredto close the set of jaws against the threaded fastener; and a ramactuator 137 (e.g., drive motor) configured to rotate the ram 136 on thehousing 134. The set of module actuators is configured to manipulate themulti-axis stage 131. The local controller 170 is configured toselectively actuate the set of module actuators, the jaw actuator 138,and the ram actuator 137 to engage and remove the threaded fastener fromthe recycled wood workpiece 115 based on the fastener removal schedule.

Furthermore, the system 100 can execute a threaded fastener removalcycle in conjunction with the threaded fastener extractor module 130.For example, the primary controller 160 can further characterize aquality of the recycled wood workpiece 115 based on internal featureswithin the virtual model and identify each threaded fastener as a screwand a characteristic of the screw (e.g., superficial, subsurface, flush,normal, non-normal relative a surface of the recycled wood workpiece115, dimension). The local controller 170 can then execute a threadedfastener removal schedule by: autonomously navigating the threadedfastener end effector 132 to a target engagement position, via the stage131 (e.g., multi-axis stage), and to a target jaw position, via the ramactuator 137 above the screw in the recycled wood workpiece 115; triggerthe jaw actuator 138 to close the set of jaws 139 to engage the set ofjaws 139 against the screw with a target retraction force; and triggerthe ram actuator 137 to rotate the ram and the set of jaws 139 toretract the screw from the recycled wood workpiece 115. Upon completionof the threaded fastener removal cycle, the local controller 170 cantrigger the stage to retract the threaded fastener end effector 132 fromthe target engagement position and trigger the jaw actuator 138 to openthe set of jaws 139 to release the threaded fastener from the set ofjaws 139 into a fastener container 145 (e.g., waste bin).

The system 100 is described herein as processing recycled woodworkpieces 115 (e.g., linear construction timber), such as dimension ornon-dimensional 2×4 or 2×6 recycled wood workpieces 115. However, thesystem 100 can additionally or alternatively process recycled woodworkpieces 115 such as: joists; rafters; wood I-beams; posts, headers;laminated timber; finger-jointed timber; plywood sheet; orientedstrandboard sheet; and/or MDF sheet; etc.

3. Method

As shown in FIGS. 2, 5, 8A, and 8B, a method S100 for removing fastenersfrom a recycled wood workpiece includes: receiving a recycled woodworkpiece in a scan volume in Block Silo; accessing a first set of X-rayscans captured by an X-ray sensor facing the scan volume occupied by therecycled wood workpiece in Block S112; detecting a set of internalfeatures representing metallic objects in the first set of X-ray scansin Block S1114; compiling the first set of X-ray scans into a virtualmodel of the recycled wood workpiece, the virtual model annotated withthe set of internal features in Block S120; receiving a section of therecycled wood workpiece in a work volume of a fastener extractor modulein Block S130; accessing a first image captured by an optical sensorfacing the work volume in Block S132; detecting an external featureextending above the section of the recycled wood workpiece in the firstimage in Block S134; and scanning the virtual model for a first internalfeature, in the set of internal features, analogous to the externalfeature of the section of the recycled wood workpiece in Block S136. Themethod S100 further includes, in response to identifying the firstinternal feature, in the set of internal features, analogous to theexternal feature of the section of the recycled wood workpiece in thevirtual model: identifying the external feature as a first metalfastener embedded in the section of the recycled wood workpiece in BlockS140; deriving a first position and a first orientation of the firstmetal fastener from the virtual model in Block S142; defining a targetengagement position for an extractor end effector, associated with thefastener extractor module, to engage the first metal fastener embeddedin the section of the recycled wood workpiece based on the firstposition and the first orientation of the first metal fastener in BlockS144; and generating a fastener removal schedule for the extractor endeffector to remove the first metal fastener from the section of therecycled wood workpiece at the first target engagement position in BlockS150.

One variation of the method S100 includes: receiving a recycled woodworkpiece populated with a set of metal fasteners in Block S110;accessing a first X-ray scan captured by an X-ray sensor facing therecycled wood workpiece in Block S112; detecting the set of metalfasteners embedded in the recycled wood workpiece based on internalfeatures detected in the first X-ray scan in Block S114; for each metalfastener in the set of metal fasteners, extracting an initial positionof the metal fastener from the first X-ray scan and extracting aninitial orientation of the metal fastener from the first X-ray scan inBlock S116; compiling the first X-ray scan into a virtual model of therecycled wood workpiece, the virtual model annotated with initialpositions and initial orientations of the set of metal fasteners inBlock S120; accessing a first image captured by an optical sensor facingthe recycled wood workpiece in Block S132; and, based on featuresdetected in the first image, detecting a first metal fastener in therecycled wood workpiece occupying the work volume and deriving a firstposition and a first orientation of the first metal fastener in BlockS142. This variation of the method S100 further includes, in response toidentifying an initial metal fastener, in the set of metal fasteners,analogous to the first metal fastener in the virtual model: isolatingthe first metal fastener in the virtual model in Block S136; andgenerating a fastener removal schedule defining a tool path for anextractor end effector to extract the first metal fastener from therecycled wood workpiece based on the first position and the firstorientation of the first metal fastener stored in the virtual model inBlock S150.

3.1 Non-threaded Fastener End Effector

As shown in FIG. 8A, one variation of the method S100 includes:receiving a section of the recycled wood workpiece in a work volume inBlock S130; accessing an image of the work volume, the image recorded byan optical sensor facing the work volume in Block S132; extracting a setof features representing the section of the recycled wood workpiece fromthe image; based on the set of features, detecting a fastener embeddedin the section of the recycled wood workpiece and extracting a firstposition and a first orientation of a head of the fastener in BlockS134; deriving a first target engagement position of a non-threadedfastener end effector, to engage the fastener, based on the firstposition of the head of the fastener in Block S144; and deriving a firsttarget jaw position to align a retraction axis of a set of jawsorthogonal to a longitudinal axis of the recycled wood workpiece basedon the orientation of the head of the fastener in Block S146. Thisvariation of the method S100 further includes, in response to drivingthe non-threaded fastener end effector to the first target engagementposition: rotating the set of jaws to the first target jaw position inBlock S152; locating the set of jaws within a threshold distance of thesection of the recycled wood workpiece spanning the head of the fastenerin Block S154; triggering a jaw actuator to drive the set of jaws intothe section of the recycled wood workpiece and close the set of jaws toengage the fastener in Block S156; and retracting the non-threadedfastener end effector to extract the fastener from the section of therecycled wood workpiece in Block S158.

3.2 Threaded Fastener End Effector

As shown in FIG. 8A, one variation of the method S100 includes:receiving a section of the recycled wood workpiece in a work volume inBlock S130; accessing an image of the work volume, the image recorded byan optical sensor facing the work volume in Block S132; extracting a setof features representing the section of the recycled wood workpiece fromthe image; based on the set of features, detecting a fastener embeddedin the section of the recycled wood workpiece and extracting a positionand an orientation of a shank of the fastener in Block S134; andderiving a first target engagement position of a threaded fastener endeffector, to engage the fastener, based on the position of the shank ofthe fastener in Block S144. This variation of the method S100 includes,in response to driving the threaded fastener end effector to the firsttarget engagement position: locating the set of jaws within a thresholddistance of the section of the recycled wood workpiece and spanning theshank of the fastener in Block S154; driving the threaded fastener endeffector to locate a rotational axis of the threaded fastener endeffector coaxial with the orientation of the shank of the fastener;triggering a jaw actuator to drive the set of jaws into the section ofthe recycled wood workpiece and close the set of jaws to engage theshank of the fastener in Block S156; and triggering a ram actuator torotate the ram and the set of jaws about the rotational axis of thethreaded fastener end effector to retract the first fastener from thesection of the recycled wood workpiece in Block S160.

4. System

As described above, the system 100 includes: an X-ray scan module 112; achassis 102; a conveyor 105; an optical sensor 110 (e.g., a 3D depthcamera, a structured light camera configured to output RGB-D depth mapsand point clouds, a two-dimensional color or hyperspectral camera, astereoscopic color camera; a thermographic camera); a fastener extractormodule (e.g., a non-threaded fastener extractor module 120, a threadedfastener extractor module 130); a metal scan module 150; and a primarycontroller 160.

4.1 X-Ray Scan Module

The X-ray scan module 112 is configured to capture a sequence ofinternal imaging data of the recycled wood workpiece 115 as a machine(e.g., a forklift) or a human operator drives the recycled woodworkpiece 115 past the X-ray scan module 112 during a first segment ofthe processing cycle. Furthermore, the X-ray scan module 112 is arrangedwithin a threshold distance of the entry of the chassis 102 of a firstfastener extractor module in a set of fastener extractor modules (e.g.,a set of non-threaded fastener extractor modules 120, a set of threadedfastener extractor modules 130) and defines a scan volume.

In one implementation, the X-ray scan module 112 includes athree-dimensional X-ray sensor facing a scan volume occupied by therecycled wood workpiece 115. In this implementation, the X-ray sensorcan capture a set of X-ray scans of the recycled wood workpiece 115 asthe machine (e.g., a forklift) or the human operator drives the recycledwood workpiece 115 past the X-ray scan module 112. The primarycontroller 160 can then compile this set of X-ray scans into athree-dimensional model (or “virtual model”)—annotated with the internalfeatures and defining a recycled wood workpiece 115 coordinate system—ofthe recycled wood workpiece 115.

In one variation, the X-ray scan module 112 includes a set ofthree-dimensional internal imaging sensors (e.g., magnetic resonancesensors, millimeter wave sensors, X-ray sensors) facing the scan volumeoccupied by the recycled wood workpiece 115. In this variation, eachinternal imaging sensor in the set of internal imaging sensors cancapture a set of internal imaging scans of the recycled wood workpiece115 as the machine (e.g., a forklift) or the human operator drives therecycled wood workpiece 115 past the X-ray scan module 112. The primarycontroller 160 can then implement methods and techniques described aboveto compile these sets of internal imaging scans into a virtualmodel—annotated with the internal features—of the recycled woodworkpiece 115.

In another implementation, the X-ray scan module 112 includes aone-dimensional X-ray line scanner arranged over (or facing laterallyacross) the scan volume occupied by the recycled wood workpiece 115. Inthis implementation, the X-ray scanner can capture a series of X-rayline scans of the recycled wood workpiece 115 as the machine (e.g., aforklift) or the human operator drives the recycled wood workpiece 115past the X-ray scan module 112. The primary controller 160 can thencompile these X-ray line scans into a two-dimensional X-ray scan of therecycled wood workpiece 115.

4.2 Chassis

The chassis 102: defines a work volume 109 and includes an exo-structurearranged about each non-threaded fastener extractor module 120 and/oreach threaded fastener extractor module 130. The exo-structure isconfigured to: support the stage and the extractor end effector of anon-threaded fastener extractor module 120 and/or a threaded fastenerextractor module 130.

In one variation, the chassis 102 includes: a first set of lateralclamps 103 to constrain lateral sides of the recycled wood workpiece 115at an input side (e.g., entry) of the chassis 102; a first set ofvertical clamps 104 to constrain vertical sides of the recycled woodworkpiece 115 at the input side of the chassis 102; a second set oflateral clamps 103 to constrain lateral sides of the recycled woodworkpiece 115 at an output side (e.g., exit) of the chassis 102; and asecond set of vertical clamps 104 to constrain vertical sides of therecycled wood workpiece 115 at the output side of the chassis 102.

4.3 Conveyor

The conveyor 105 is configured to receive the recycled wood workpiece115 populated with metal fasteners and is configured to constrain asection of the recycled wood workpiece 115 within the work volume 109 ofa fastener extractor module. The conveyor 105 also includes a set of(e.g., two) rollers arranged on each side of a longitudinal axis of thesystem 100 and cooperate to engage and position a recycled woodworkpiece 115 along the longitudinal axis of the system 100.

In one implementation the conveyor 105 includes: an input roller 106coupled to an input side of a lateral axis of the threaded fastenerextractor module; a first set of standoffs 108 extending radially fromthe input roller 106, defining a length greater than a nominal fastenerlength, and configured to locate the recycled wood workpiece 115 at theinput side; and an output roller 107 coupled to an output side of thelateral axis of the threaded fastener extractor module and includes asecond set of standoffs 108 extending radially from the output roller107, defining the length greater than the nominal fastener length, andconfigured to locate the recycled wood workpiece 115 at the output side.

In one variation, the first set of standoffs 108 extend radially fromthe input roller 106 and exhibit triangular cross-sections with verticesoffset from the input roller 106. The second set of standoffs 108 alsoextend radially from the output roller 107 and exhibit triangularcross-sections with vertices offset from the output roller 107.Accordingly, the first set of standoffs 108 and the second set ofstandoffs 108 cooperate to locate an adjacent recycled wood workpiece115 between the input roller 106 and the output roller 107 during theprocessing and the fastener removal cycles.

Additionally, the conveyor 105 includes: a set of (e.g., two, three,four) adjustable clamps configured to receive and retain the recycledwood workpiece. For example, the conveyor 105 can include: a set oflateral clamps 103 to constrain lateral sides of the recycled woodworkpiece 115 at the input side of the chassis 102; and a set ofvertical clamps 104 to constrain vertical sides of the recycled woodworkpiece 115 at the input side of the chassis 102.

In this implementation, the input roller 106, the output roller 107, andthe set of (e.g., two, four) adjustable clamps cooperate to receive andretain the recycled wood workpiece 115—in six degrees of freedom—duringthe processing cycle. Additionally, the set of rollers and the set ofadjustable clamps cooperate to: receive and retain the recycled woodworkpiece 115 during the processing cycle; and permit fastener extractormodules to access and remove fasteners—embedded and/or extending abovesurfaces of the recycled wood workpiece 115 occupying the work volume109—during a fastener removal cycle.

For example, at a first time, the local controller 170 can trigger theconveyor 105 to rotate the input roller 106 to locate a section of therecycled wood workpiece 115 cantilevered within the work volume 109 of afastener extractor module—and therefore a set of fasteners extendingabove this section of the recycled wood workpiece 115—as the system 100autonomously scans this section of the recycled wood workpiece 115 witha set of optical sensors 110. The local controller 170 can then: actuatea set of lateral clamps 103 to constrain lateral sides of the recycledwood workpiece 115 at the input side of the chassis 102; and actuate aset of vertical clamps 104 to constrain vertical sides of the recycledwood workpiece 115 at the input side of the chassis 102. Thus the set oflateral clamps 103 and the set of vertical clamps 104 enable a fastenerextractor module to remove fasteners from this section of the recycledwood workpiece 115 during the fastener removal cycle. At a second time,the local controller 170 can: trigger the conveyor 105 to rotate theinput roller 106 to and the output roller 107 to locate the section ofthe recycled wood workpiece 115 outside the fastener extractor moduletoward a next fastener extractor module. Additionally, the input roller106 can locate a next section of the recycled wood workpiece 115 withinthe work volume 109 of the fastener extractor module—and therefore anext set of fasteners extending above this section of the recycled woodworkpiece 115—as the system 100 autonomously scans this section of therecycled wood workpiece 115 with the set of optical sensors 110. Thelocal controller 170 can repeat these methods and techniques for eachother fastener in the sets of fasteners and for each other section ofthe recycled wood workpiece 115 to remove fasteners from the recycledwood workpiece 115.

4.4 Optical Sensor

The system further includes an optical sensor 110 and/or a set of (e.g.,two, three) optical sensors 110 coupled to each fastener extractormodule (e.g., non-threaded fastener extractor module 120, threadedfastener extractor module 130). The optical sensor 110 faces the workvolume 109 and is configured to capture a set of images of the workvolume 109 occupied by the recycled wood workpiece 115 during aprocessing cycle and/or fastener removal schedule.

Furthermore, the primary controller 160 can access the set of images ofthe work volume 109 from each optical sensor 110, in the set of opticalsensors 110, and stitch these images into a 3D point cloud of the workvolume 109 based on: placement of each optical sensor within thecoordinate system of the fastener extractor module (e.g., non-threadedfastener extractor module 120, threaded fastener extractor module 130);and analogous overlapping features in images recorded by each opticalsensor 110, in the set of optical sensors 110.

4.5 Non-threaded Fastener Extractor Module

Each non-threaded fastener extractor module 120 includes: a stage 121(or “a multi-axis stage”); a non-threaded fastener end effector 122; aset of module actuators; and a local controller 170. The multi-axisstage 121 is arranged in a work volume 109 defined by the chassis 102and faces the recycled wood workpiece 115. The non-threaded fastener endeffector 122 is supported by the multi-axis stage 121, which includes alateral stage and a longitudinal stage. The non-threaded fastener endeffector 122 includes: a bearing plate 123; and a vertical stage 124arranged on the multi-axis stage 121 and configured to support thebearing plate 123, advance the bearing plate 123 toward a non-threadedfastener in a recycled wood workpiece 115 occupying the work volume 109,and retract the bearing plate 123 to withdraw the non-threaded fastenerfrom the recycled wood workpiece 115. The non-threaded fastener endeffector 122 also includes: a jaw head 126 arranged on and rotationallycoupled to a distal end of the bearing plate 123; a set of jaws 128pivotably coupled to a distal end of the jaw head 126; a yaw actuator127 arranged on the bearing plate 123, coupled to the jaw head 126, andconfigured to pan (i.e., rotate) the jaw head 126 about a yaw axis ofthe non-threaded fastener end effector 122; and a jaw actuator 125arranged on the vertical stage 124, coupled to the set of jaws 128 via ajaw linkage including a gear and configured to close the set of jaws 128to engage the set of jaws 128 against the non-threaded fastener and toopen the set of jaws 128 to release the non-threaded fastener from theset of jaws 128.

4.6 Threaded Fastener Extractor Module

Each threaded fastener extractor module 130 includes: a multi-axis stage131; a threaded fastener end effector 132; a set of module actuators;and a local controller 170. The multi-axis stage 131 is arranged in awork volume 109 defined by the chassis 102 and faces the linear sledstage. The threaded fastener end effector 132 is supported by themulti-axis stage 131 and includes: a housing 134; a ram 136 arranged andconfigured to rotate in the housing 134; a set of jaws 139 arranged on adistal end of the ram 136; a jaw actuator 138 configured to close theset of jaws 139 against the threaded fastener; and a ram actuator 137(e.g., drive motor) configured to rotate the ram 136 on the housing 134.The set of module actuators is configured to manipulate the multi-axisstage 131. The local controller 170 is configured to selectively actuatethe set of module actuators, the jaw actuator 138, and the ram actuator137 to engage and remove the threaded fastener from the recycled woodworkpiece 115 based on the fastener removal schedule.

4.7 Multiple End Effectors Per Work Volume

In one variation, each non-threaded fastener extractor module 120 caninclude multiple independently-operable instances of the non-threadedfastener end effector 122 such as: two, three, or four instances of thenon-threaded fastener end effector 122 distributed radially about thenon-threaded fastener extractor module 120 in each work volume 109; andthat cooperate to access and remove non-threaded fasteners from all foursides of a section of a recycled wood workpiece 115 occupying the workvolume 109.

Similarly, each threaded fastener extractor module 130 can includemultiple independently operable instances of the threaded fastener endeffector 132 such as: two, three, or four instances of the threadedfastener end effector 132 distributed radially about the threadedfastener extractor module 130 in each work volume 109; and thatcooperate to access and remove threaded fasteners from all four sides ofa section of a recycled wood workpiece 115 occupying the work volume109.

For example, a first non-threaded fastener end effector 122 and/orthreaded fastener end effector 132 faces a first side of the section ofthe recycled wood workpiece 115 within the work volume 109 of thefastener extractor module and the set of jaws 128, 139 are configured toengage and retain metal fasteners (e.g., nails, staples, screws) fromthe first side of the section of the recycled wood workpiece 115. Inthis example, the fastener extractor module includes a second stage 121,131 supported by the chassis 102, a second non-threaded fastener endeffector 122, and/or threaded fastener end effector 132: facing a secondside orthogonal to the first side of the section of the recycled woodworkpiece 115 within the work volume 109; supported and manipulated onthe chassis 102 via the second stage 121, 131; including a second set ofjaws 128, 139 configured to engage and retain metal fasteners (e.g.,nails, staples, screws) from the second side of the section of therecycled wood workpiece 115; and including a second jaw actuator 125,138 configured to actuate the second set of jaws 128, 139. The localcontroller 170 of the fastener extractor module can access a secondimage of the work volume 109 captured by the optical sensor 110 andbased a second set of features detected in the second image: detect asecond fastener in the second side of the section of the recycled woodworkpiece 115 occupying the work volume 109; and derive a secondposition and a second orientation of the second fastener in the workvolume 109.

The local controller 170 can then: define a second target engagementposition of the second non-threaded fastener end effector 122 and/orthreaded fastener end effector 132, to engage the second fastener, basedon the second position and the second orientation of the secondfastener; derive a fastener extraction order for the first stage 121,131 and the second stage 121, 131 based on the first engagement positionand the second engagement position; trigger the second stage 121, 131 todrive the second non-threaded fastener end effector 122 to the secondtarget engagement position according to the extraction order; triggerthe second jaw actuator 125, 138 to drive the second set of jaws 128,139 to engage the second fastener in the second side of the section ofthe recycled wood workpiece 115; and trigger the second stage 121, 131to retract the second non-threaded fastener end effector 122 from thesecond target engagement position to extract the second fastener fromthe recycled wood workpiece 115. Additionally or alternatively, thelocal controller 170 can: trigger the second ram actuator 137 to rotatethe second ram 136 and the second set of jaws 139 about the secondrotational axis of the second threaded fastener end effector 132 toretract the second fastener from the second side of the section of therecycled wood workpiece 115.

4.7.1 Fastener Container

In one variation, the system 100 includes a single fastener container145 (e.g., waste bin) per work volume 109, per set of non-threadedfastener extractor modules 120, per set of threaded fastener extractormodules 130, per individual non-threaded fastener extractor module 120,or per individual threaded fastener extractor module 130. In oneimplementation, the fastener container 145 includes a break beam ormotion sensor configured to detect release of a fastener—from a threadedfastener extractor module 130 and/or a non-threaded fastener extractormodule 120—into the fastener container 145 at the conclusion of eachfastener removal cycle.

For example, the system 100 can include a fastener container 145 (e.g.,a waste bin): arranged below the chassis 102; defining an aperture; andconfigured to store extracted fasteners from the recycled wood workpiece115. The fastener container 145 can include a break beam sensor coupledto the fastener container 145 and configured to output a signalcorresponding to motion across the aperture. In this example, the localcontroller 170 of the non-threaded fastener extractor module 120 and/orthe threaded fastener extractor module 130 can: trigger the jaw actuatorto disengage the set of jaws to release a fastener into the fastenercontainer 145; and confirm extraction of the fastener into the fastenercontainer 145 in response to the break beam sensor detecting motionacross the aperture within a threshold duration (e.g., 10 seconds, 20seconds, 30 seconds) of release of the set of jaws 128, 139 by the jawactuator 125.

4.8 Metal Scan Module

The metal scan module 150 is configured to capture a sequence of metalscan data of the recycled wood workpiece 115 as the local controller 170of a non-threaded fastener extractor module 120 and/or a threadedfastener extractor module 130 drives the recycled wood workpiece 115past the metal scanner during a last segment of the processing cycle.Alternatively, the metal scan module 150 is configured to capture a setof metal scans of the recycled wood workpiece 115 as the machine (e.g.,forklift) or a human operator drives the recycled wood workpiece 115from a fastener extractor module to the metal scan module 150.

In one implementation, the metal scan module 150 includes aone-dimensional metal line scanner arranged over (or facing laterallyacross) the recycled wood workpiece 115. In this implementation, themetal scanner can transmit an electromagnetic field into the recycledwood workpiece 115 to detect any fasteners (e.g., metal objects) thatwent undetected during previous segments of the processing cycle. Then,in response to absence of fasteners in the recycled wood workpiece 115,the primary controller 160 can trigger the conveyor 105 to drive therecycled wood workpiece 115 forward to a recycled wood workpiece 115pallet and reset the conveyor 105 to a home position.

Alternatively, in response to detecting a fastener and/or a set offasteners in the recycled wood workpiece 115, the primary controller 160can trigger the conveyor 105 to drive the recycled wood workpiece 115forward to a recycled wood workpiece 115 receival pallet to resect asection of the recycled wood workpiece 115 containing the fastenerand/or to restart the processing cycle.

In one variation, the local controller 170 of a non-threaded fastenerextractor module 120 and/or a threaded fastener extractor module 130 cangenerate a resection schedule to resect a section of the recycled woodworkpiece 115 containing the fastener. For example, in response toabsence of correlation between an external feature—detected in an imagecaptured by an optical sensor—of the section of the recycled woodworkpiece 115 to an internal feature in the virtual model, the primarycontroller 160 can: define a bounding region containing the externalfeature in the image; flag the bounding region with a resection flag;generate a resection schedule to resect a subsection of the recycledwood workpiece 115 corresponding to the bounding region in the image;and assign the resection schedule to a corresponding fastener extractormodule to resect the subsection of the recycled wood workpiece 115.

4.9 Primary Controller

The primary controller 160 is coupled to actuators and sensors withinthe system 100 and executes methods and techniques described below toprocess a recycled wood workpiece 115 during a processing cycle.

5. Processing Cycle

In one implementation, at the start of a processing cycle, the humanoperator or the machine (e.g., forklift) loads a recycled wood workpiece115 onto the conveyor 105—and therefore the set of (e.g., two) spikedrollers—and the primary controller 160 can then actuate the set ofadjustable clamps to receive and retain the recycled wood workpiece 115.The primary controller 160 then initiates the processing cycle.

5.1. Processing Cycle: Initial Imaging

The primary controller 160 can: receive a recycled wood workpiece 115 ina scan volume; access a set of X-ray scans captured by an X-ray sensorfacing the scan volume occupied by the recycled wood workpiece 115;detect a set of internal features representing metallic objects in theset of X-ray scans; and compile the first set of X-ray scans into athree-dimensional representation (or “virtual model”) of the recycledwood workpiece. A first fastener extractor module can receive a sectionof the recycled wood workpiece in a work volume 109. The primarycontroller can then: access an image, in a set of images, captured bythe optical sensor 110 arranged within the fastener extractor module;detect external features extending above the section of the recycledwood workpiece 115; scan the virtual model to identify each externalfeature with an analogous internal feature; identify each externalfeature as a metal fastener; and generate a fastener removal schedulefor each external feature.

5.2 Processing Cycle: Virtual Model

The primary controller 160 compiles the set of X-ray scans into avirtual model of the recycled wood workpiece 115, such as depicting:internal features, representing metallic objects, and defects of therecycled wood workpiece 115.

In one implementation in which the X-ray scan module includes two fixedperpendicular line scanners or an X-ray sensor that sweeps across twoaxes perpendicular to the recycled wood workpiece 115 as a machine(e.g., forklift) and/or human operator advances the recycled woodworkpiece 115 toward a first fastener extractor module, the system 100can: compile the sequence of X-ray scan data captured by these X-rayscanners into a three-dimensional representation (or “virtual model”) ofthe recycled wood workpiece 115 annotated with these internal features(e.g., metallic objects and defects).

Furthermore, the primary controller 160 can: access an X-ray scan of therecycled wood workpiece 115 occupying the scan volume; detect a set ofinternal features (i.e., set of metal fasteners) populated in therecycled wood workpiece 115; detect a helical ridge fastener in the setof metal fasteners based on a features detected in the X-ray scan;extract an initial position and an initial orientation of the helicalridge fastener in the set of metal fasteners; correlate the featuresrepresenting the helical ridge fastener with known features of threadedfasteners from a threaded fastener database; compile correlations intothe virtual model (e.g., three-dimensional model) of the work volume;and label the helical ridge fastener in the virtual model with athreaded fastener type, the initial position, and the initialorientation. The primary controller 160 can then: isolate a subsectionin the virtual model containing the threaded fastener label; isolate asecondary subsection of the recycled wood workpiece 115 in animage—captured by the optical sensor facing the work volume of afastener extractor module—corresponding to the subsection in the virtualmodel; extract a subset of features from a region in the image depictingthe secondary subsection of the recycled wood workpiece 115 in theimage; identify the subset of features as a head of a first fastenerdetected in the image; map the initial position and initial orientationof the helical ridge fastener from the subsection of the virtual modelto the fastener head identified in the image; and identify the fasteneras the helical ridge fastener in response to the first position and thefirst orientation of the fastener—extracted from the image—matching theinitial position and the initial orientation of the helical ridgefastener from the virtual model.

Similarly, the primary controller 160 can implement these methods andtechniques to detect a smooth shank fastener in the set of metalfasteners based on features detected in the X-ray scan; extract aninitial position and an initial orientation of the smooth shank fastenerin the set of metal fasteners; correlate the features representing thesmooth shank fastener with known features of non-threaded fasteners froma non-threaded fastener database; compile correlations into the virtualmodel of the work volume; and label the smooth shank fastener in thevirtual model with a non-threaded fastener type, the initial position,and the initial orientation. The primary controller 160 can then:isolate a subsection in the virtual model containing the non-threadedfastener label; isolate a secondary subsection of the recycled woodworkpiece 115 in the image corresponding to the subsection in thevirtual model; extract a subset of features from a region in the imagedepicting the secondary subsection of the recycled wood workpiece 115 inthe image; identify the subset of features as a head of a fastenerdetected in the image; map the initial position and initial orientationof the smooth shank fastener from the subsection of the virtual model tothe fastener head detected in the image; and identify the fastener asthe smooth shank fastener in response to the first position and thefirst orientation—extracted from the image—of the fastener matching theinitial position and the initial orientation of the first smooth shankfastener.

However, the primary controller 160 can implement any other method ortechnique to generate a representation of the internal features of therecycled wood workpiece 115 based on X-ray data collected by the X-rayscan module.

5.2 Processing Cycle: Internal Recycled Wood Workpiece Characteristics

The primary controller 160 can also detect internal characteristics andfeatures of the recycled wood workpiece 115 based on these X-ray scans,such as including: splits; holes; rot; embedded metal (i.e., metallicobjects fully contained within the recycled wood workpiece 115); knots;and/or fasteners (e.g., metallic objects that extend above surfaces ofthe recycled wood workpiece 115).

In one implementation, the primary controller 160: compiles the sequenceof X-ray scan data captured by these X-ray scanners into a two- orthree-dimensional representation of internal features (i.e., defects) inthe recycled wood workpiece 115; and detects and extractstwo-dimensional or three-dimensional constellations of features fromthis internal representation of the recycled wood workpiece 115. Forexample, the primary controller 160 can: implement blob detection,object recognition, and/or other techniques to group individual featuresdetected in the internal representation of the recycled wood workpiece115 into a set of feature constellations; implement artificialintelligence and/or machine learning techniques to correlate theseconstellations of features with known characteristics of splits, holes,rot, embedded metal, and knots; and label these constellations offeatures in the internal representation of the recycled wood workpiece115 accordingly and/or project these constellations and labels onto thevirtual model.

Alternatively, the primary controller 160 can access a database oftemplate images representing various examples of these defect types,such as derived from scan data of previous recycled wood workpieces 115processed by the system 100. Then, for each feature constellation inthis set, the primary controller 160 can: compare the featureconstellation to a template image in the database; and characterize asimilarity of the feature constellation to the template image. If thissimilarity exceeds a threshold similarity, the primary controller 160can annotate the feature constellation with a defect type and otherattributes stored in or associated with the template image.

However, the primary controller 160 can implement any other method ortechnique to detect or characterize internal features of the recycledwood workpiece 115 based on X-ray scan data captured by the X-ray scanmodule.

5.4 Processing Cycle: Superficial Fasteners

The primary controller 160 can also interpret types, positions, and/ororientations of fasteners on each side of the recycled wood workpiece115 from these X-ray and optical scan data.

5.4.1. Recycled Wood Workpiece Faces

In one implementation, the primary controller 160 implements planedetection techniques to detect a set of faces (e.g., six “sides”) in thevirtual model that are approximately perpendicular. For each facedetected in the virtual model, the primary controller 160: isolates aset of superficial points in the virtual model that represent this face;calculates a plane characterized by least error (e.g., shortestEuclidean distance) between the plane and the set of superficial points;and stores the plane as a ground plane of this face in the virtualmodel.

In another implementation, the primary controller 160: implements planedetection techniques to detect a set of faces (e.g., six sides) in thevirtual model that are approximately perpendicular; retrieves virtualrecycled wood workpiece 115 geometry, such as a virtual rectangularcuboid (or virtual rectangular prism); projects the virtual recycledwood workpiece 115 geometry onto the virtual model; resizes and warps(e.g., curve) faces of the virtual recycled wood workpiece 115 geometryto minimize error between each face of the virtual recycled woodworkpiece 115 geometry and points representing the corresponding facesof the virtual model; and stores the faces of the first recycled woodworkpiece 115 geometry as ground planes of the faces in the virtualmodel.

For example, the primary controller 160 can detect a set of faces of therecycled wood workpiece 115 in the virtual model and access a templategeometry representing geometry of known faces of the recycled woodworkpiece 115. Then, for each face in the set of faces, the primarycontroller 160 can: isolate a set of superficial points of the face inthe virtual model; project the template geometry of a known face ontothe set of superficial points of the face in the virtual model;calculate an offset distance between the template geometry of the knownface and the set of superficial points of the face in the virtual model;and, in response to the offset distance falling below a threshold offsetdistance, store the template geometry of the known face as a groundplane of the face in the virtual mode.

5.4.2 Fastener Locations

In one implementation, for a first face in the virtual model, theprimary controller 160: scans the virtual model for discrete clusters ofpoints extending above the ground plane of the first face andrepresenting internal features; and labels each cluster of pointsrepresenting an internal feature as a possible fastener.

Then, for a first cluster of points representing a first possiblefastener, primary controller 160 can: isolate a first subset ofpoints—representing a shank of an initial internal feature—intersecting(e.g., nearest) the ground plane of the first face in the virtual model;calculate a first centroid of the first subset of points; isolate asecond subset of points of a first plane—representing a head of theinitial internal feature (e.g., the top surface of a flat head of a nailor a top surface of a flat head of a screw or a top surface of aconnecting segment and/or leg of a staple)—within a threshold distanceof the ground plane of the first face (e.g., furthest from the groundplane of the first face); calculate a second centroid of the secondsubset of points; and calculate a first vector—such as within acoordinate system of the virtual model—between the first subset ofpoints and the second subset of points based on the first and secondcentroids. The primary controller 160 can then label the first clusterof points in the virtual model with the first vector, representing aninitial orientation and an initial position of the head of the initialinternal feature.

The primary controller 160 repeats this process for each other clusterof points representing possible fasteners and repeats this process foreach other side of the virtual model to annotate all possible recycledwood workpieces 115, their orientations, and their head or connectingsegment locations.

4.2 Fastener Type+Virtual Model

Generally, the primary controller 160 can implement artificialintelligence, template matching, computer vision techniques, and/orstatistical methods, etc. to: extract a set of features from a clusterof points representing a possible fastener in the virtual model or fromthe optical scan data directly; and to match (or “map”) the set offeatures to a particular fastener type.

More specifically, the primary controller 160 can: detect a first subsetof internal features representing metallic objects from the X-ray scans;characterize a first smoothness quality of the first subset of internalfeatures; detect a second subset of internal features representingmetallic objects from the X-ray scans; and characterize a secondsmoothness quality of the second subset of internal features. Then, inresponse to the first smoothness quality exceeding a thresholdsmoothness quality, the primary controller 160 can label the firstsubset of internal features with a non-threaded fastener type (e.g.,nail, staple, nail retainer) in the virtual model. Similarly, inresponse to the second smoothness quality falling below the thresholdsmoothness quality, the primary controller 160 can label the secondsubset of internal features with a threaded fastener type (e.g., screw)in the virtual model.

In one implementation, for each cluster of points labeled as a metallicobject (e.g., possible fastener), the primary controller 160 can: detectthe first face of the recycled wood workpiece 115 in the virtual model;scan the virtual model for a set of points—representing the initialmetallic object—extending above a ground plane of the first face;isolate a first subset of points—representing a head of the initialmetallic object—extending above the ground plane of the first face(e.g., outside of the recycled wood workpiece 115 volume and furthestfrom the surface of the recycled wood workpiece 115); characterize adepth and a breadth of the head of the initial metallic object based onthe first subset of points; isolate a second subset ofpoints—representing a shank of the initial metallic object—intersectingthe ground plane of the first face in the virtual model (e.g., withinthe recycled wood workpiece 115 volume and further from the surface ofthe recycled wood workpiece 115); and characterize a curvature of theshank of the initial metallic object based on the second subset ofpoints. The primary controller 160 can then: calculate an aspect ratioof the head based on the depth and breadth of the head of the initialmetallic object; in response to the aspect ratio exceeding a thresholdaspect ratio and in response to the curvature of the shank of theinitial metallic object exceeding a threshold curvature, identify thefastener type of the initial metallic object as a bent nail; annotatethe set of points in the virtual model with a bent nail fastener type;and flag the set of points in the virtual model with a bent nail removalflag.

The primary controller 160 can also: characterize an aspect ratio of thewidth versus depth of the head; characterize an angle of the side ofhead; and characterize a curvature of the shank fastener, such as a)proportional to an error between the cluster of points that representthe fastener and the vector that defines the predicted orientation ofthe fastener or b) based on a radius of an arc projected onto thevirtual model characterized by least error between the cluster of pointsthat represent the fastener and the arc. Accordingly, the primarycontroller 160 can identify the possible fastener as a screw if: theaspect ratio is low; the head angle indicates that the head defines acountersunk profile; and/or if the curvature is less than a thresholdradius. Otherwise, the primary controller 160 can identify the fasteneras a nail.

The primary controller 160 can then: annotate a cluster of points in thevirtual model identified as a screw with a screw removal flag; andsimilarly annotate a cluster of points in the virtual model identifiedas a nail with a nail removal flag.

In yet another implementation, for each cluster of points labeled as ametallic object (e.g., possible fastener), the primary controller 160can: detect the first face of the recycled wood workpiece 115 in thevirtual model; scan the virtual model for a set of points—representingthe initial metallic object—extending above a ground plane of the firstface; isolate a first subset of points—representing a crown or body ofthe initial metallic object—extending above the ground plane of thefirst face; isolate a second subset of points—representing a first legof the initial metallic object—orthogonal to the first subset of pointsand intersecting the ground plane of the first face (e.g., within therecycled wood workpiece 115 volume and adjacent the first subset ofpoints); isolate a third subset of points—representing a second leg ofthe initial metallic object—orthogonal to the first subset of points andopposite the second subset of points intersecting the ground plane ofthe first face; and characterize a dimension of the initial metallicobject based on the first, second, and third subsets of pointsrepresenting the first leg, the crown, and the second leg. The primarycontroller 160 can then, in response to the dimension of the initialmetallic object exceeding a threshold dimension: identify the fastenertype of the initial metallic object as a staple; annotate the set ofpoints in the virtual model with a staple fastener type; and flag theset of points in the virtual model with the staple removal flag.

5.4.4 Fastener Data from X-Ray Scans

In the variation described above in which the X-ray scanner captures 3DX-ray data of the recycled wood workpiece 115, the primary controller160 can also assimilate superficial 3D optical data representing afastener and adjacent internal X-ray data representing a metallic objectinto one composite representation of the fastener. The primarycontroller 160 can then implement methods and techniques described aboveto: detect a first cluster of X-ray-based points representing the distalend of the fastener—embedded in the recycled wood workpiece 115—in thevirtual model; calculate a first centroid of the first cluster ofpoints; isolate a second cluster of optical-based points furthest fromthe ground plane of the corresponding face of the virtual model;calculate a second centroid of the second cluster of optical-basedpoints; calculate a vector—such as within a coordinate system of thevirtual model—extending between the first and second centroids; andstore this vector as the orientation of the fastener.

In a similar implementation, the primary controller 160 can: calculatean arc characterized by minimum error (e.g., minimum aggregate Euclideandistance) between the arc and X-ray- and optical-based points thatrepresent the fastener in the virtual model; calculate a tangent of thisarc at its intersection with the ground plane of the corresponding facein the virtual model; and store a vector—defining this tangent in thecoordinate system of the virtual model—as the orientation of thefastener.

In this variation, the primary controller 160 can also verify or predictthe fastener type based on the X-ray scan data. In one implementation,the primary controller 160: identifies a cluster of points in the X-rayscan data depicting a cylindrical metallic object within the volume ofthe recycled wood workpiece 115 (and contiguous with a fasteneridentified about a ground plane of a face in the virtual model);identifies this cluster of points as a shank or barrel of a fastener;and characterizes a smoothness quality of the shank or barrel of thefastener. For example, the primary controller 160 can: map a sawtoothpattern onto the cluster of points, such as extending between the distaland proximal ends of the fastener as described above; calculate anamplitude and frequency of the sawtooth pattern that minimizes an error(e.g., a Euclidean distance) between the sawtooth pattern and thecluster of points; and characterize smoothness of the fastener inverselyproportional to the amplitude and frequency. The primary controller 160can then: identify the fastener as a nail if smoothness exceeds athreshold smoothness (e.g., the amplitude and frequency of the projectedsawtooth pattern fall below threshold values); and otherwise identifythe fastener as a threaded fastener (e.g., a screw).

For example, the local controller 170 can: detect a set of internalfeatures representing metallic objects in the X-ray scans within thevirtual model; access an image captured by the optical sensor 110 facingthe work volume 109; detect an external feature extending above thesection of the recycled wood workpiece 115 in the image; extract aposition and orientation of the external feature in the image; detect afirst face of the recycled wood workpiece 115 within the virtual modelcontaining the external feature; characterize a smoothness quality ofthe first internal feature corresponding to the external feature basedon the virtual model; and, in response to the smoothness qualityexceeding a threshold smoothness quality, identify the external featureas a nail embedded in the first face of the recycled wood workpiece 115.The local controller 170 can then: define a target engagement positionfor a non-threaded fastener end effector 122 (e.g., nail extractor endeffector), associated with a non-threaded fastener extractor module 120(e.g., nail fastener extractor module), to engage the nail embedded inthe first face of the recycled wood workpiece 115 based on the positionand orientation of the nail; and derive a nail removal schedule for thenon-threaded fastener end effector 122 to remove the nail from the firstface of the recycled wood workpiece 115 at the target engagementposition.

Alternatively, in response to the smoothness quality falling below athreshold smoothness quality, the local controller 170 can identify theexternal feature as a screw embedded in the first face of the recycledwood workpiece 115. The local controller 170 can then: define a targetengagement position for a threaded fastener end effector 132 (e.g.,screw extractor end effector), associated with a threaded fastenerextractor module 130 (e.g., screw fastener extractor module), to engagethe screw embedded in the first face of the recycled wood workpiece 115based on the position and orientation of the screw; and derive a screwremoval schedule for the threaded fastener end effector 132 to removethe screw from the first face of the recycled wood workpiece 115 at thetarget engagement position.

In one variation, the primary controller 160 can: extract a profile ofthe cluster of points from the X-ray scan data; implement templatematching to match the profile to a stored nail or threaded fastenerprofile; and/or implement artificial intelligence to identify a fastenertype corresponding to this profile. In this variation, the primarycontroller 160 can then fuse this X-ray-based predicted fastener typewith an optical-based predicted fastener type of an adjacent orcontiguous fastener detected above the ground plane on the correspondingside of the virtual model to refine or verify the type of the fastener.For example, the primary controller 160 can: implement methods andtechniques described above to derive a first fastener type predictionbased on images from the optical sensor representing external featuresof the recycled wood workpiece 115; implement these methods andtechniques to derive a second fastener type prediction based on X-rayscan data representing internal features of the recycled wood workpiece115; and combine (or “fuse”) the first and second fastener typepredictions into a final prediction for the type of the fastener, suchas by calculating a combination of these predictions weighted by theircorresponding confidence scores.

The primary controller 160 can implement this process for each otherfastener and/or embedded metal detected in the X-ray scan and/or thevirtual model.

5.4.5 Processing Cycle: Recycled Wood Workpiece Quality from X-Ray Scans

The primary controller cam also characterize an aggregate quality of thewhole recycled wood workpiece 115 proportional to its total length andinversely proportional to: quantity of splits, length of splits,proximity of splits to the longitudinal center of the recycled woodworkpiece 115; size and quantity of through and blind holes; length ofrecycled wood workpiece 115 containing rot and proximity of rot to thelongitudinal center of the recycled wood workpiece 115; frequency ofembedded metal and proximity of embedded metal to the longitudinalcenter of the recycled wood workpiece 115; frequency and size of knots;and/or frequency of fasteners in the recycled wood workpiece 115. Then,if the aggregate quality of the whole recycled wood workpiece 115exceeds a threshold aggregate quality, the primary controller cangenerate a fastener removal schedule as described below to removefasteners without removing sections of the recycled wood workpiece 115or otherwise cutting down the length of the recycled wood workpiece 115.Otherwise, the primary controller can isolate discard segments to remove(or “resect”) from the recycled wood workpiece 115 to increase aggregatequality of the remaining target segments of the recycled wood workpiece115.

In one implementation, the primary controller segments the total lengthof the recycled wood workpiece 115 into segments of a unit length (e.g.,one inch). For each segment of the recycled wood workpiece 115, theprimary controller implements methods and techniques described above to:detect a set of defects present in this segment of the recycled woodworkpiece 115; and calculate segment quality of this segment of therecycled wood workpiece 115 based on the types and scopes (e.g., sizesof holes, depths of splits, porosity from dry rot, quantity offasteners). If the segment quality of a segment is less than a thresholdsegment quality, the primary controller can locate a set of resectionflags on the virtual model to define removal of this segment from therecycled wood workpiece 115.

Furthermore, if the combined (e.g., average) quality of any contiguoussequence of segments of the recycled wood workpiece 115 is less than athreshold segment group quality, the primary controller can locate a setof resection flags on the virtual model for removal of this contiguoussequence of segments.

The primary controller can then prescribe sub-lengths of the recycledwood workpiece 115 between this set of resection flags. For eachsub-length of the recycled wood workpiece 115, the primary controller160 can: implement methods and techniques described above to recalculatean aggregate quality of the sub-length; flag the sub-length in thevirtual model for fastener removable and reclamation (e.g., up-recyclingback into a full-length recycled wood workpiece 115) if the aggregatequality of the sub-length exceeds the threshold aggregate quality and aminimum length (e.g., one foot); and/or flag the sub-length in thevirtual model for fastener removal and recycling (e.g., down-cyclinginto OSB or MDF) if the aggregate quality of the sub-length is less thanthe threshold aggregate quality and/or less than the minimum length(e.g., one foot) and the primary controller detects no embedded metalinside the segment (i.e., absence of metal not connected to a nail orscrew head at or above the surface of the recycled wood workpiece 115).Otherwise, if the aggregate quality of the sub-length is less than thethreshold aggregate quality and/or less than the minimum length (e.g.,one foot) and if the primary controller detects metal fully embedded inthe segment, the primary controller 160 can flag the sub-length in thevirtual model for discard (and no fastener removal).

5.4.6 Fastener Removal Schedule

Therefore, the primary controller 160 can execute the foregoing methodsand techniques to: generate a virtual model representing internal and/orexternal features of the recycled wood workpiece 115; detect locations,orientations, and types of fasteners on the recycled wood workpiece 115;characterize quality of the recycled wood workpiece 115; identifysegments of the recycled wood workpiece 115 to discard; and annotate thevirtual model with cut locations for discarding recycled wood workpiece115 segments and removing fasteners.

The primary controller 160 can then: define a target engagement positionfor an extractor end effector, of a fastener extractor modulecorresponding to a type of each fastener, to engage each fastenerembedded within and/or extending above the section of the recycled woodworkpiece based on position and orientations of each fastener; andgenerate a fastener removal schedule executable by the system 100 toselectively remove fasteners from the recycled wood workpiece 115. Morespecifically, the primary controller 160 can generate a fastenerextraction order—containing fastener removal schedules for each fastenerextractor module—that assigns each fastener, flagged for removal in thevirtual model, for removal by one fastener extractor module of thecorresponding fastener type at a target engagement position; andprescribes a tool path to each flagged fastener for its removal, such asbased on the type and the orientation of each flagged fastener.

6. Variation: Sled Based Conveyance+Optical Scan Module

One variation of the system 100 includes: a chassis 102; a sled; a sledactuator; a sled position sensor; an X-ray scanner; an optical scanner;a set of fastener extractor modules (e.g., non-threaded fastenerextractor modules 120, threaded fastener extractor modules 130); a metalscanner; and a primary controller 160.

6.1 Chassis

The chassis 102: defines a work volume 109 and includes an exo-structurearranged about each non-threaded fastener extractor module 120 and/oreach threaded fastener extractor module 130. The exo-structure isconfigured to: support the stage of a non-threaded fastener extractormodule 120 and/or a threaded fastener extractor module 130; and supportthe extractor end effector of a non-threaded fastener module 120 and/ora threaded fastener extractor module 130.

In one implementation, the chassis 102: supports the linear sled stage,which extends from the entry of the chassis 102 to the exit of thechassis 102; and includes an exo-structure arranged about the linearsled stage and configured to support arrays (e.g., columns) of fastenerextractor modules about the linear sled stage.

In one variation, the chassis 102 includes: an assembly of extrudedmetal profiles (e.g., aluminum, steel) that form a set of cuboidexoskeletons arranged in series. Each cuboid exoskeleton can: define awork volume 109 (e.g., operating theater); include mounting points for afastener extractor module, scanner, or other actuator; and support thelinear sled stage proximal the sagittal axis of the cuboid exoskeleton.In this implementation, the linear sled stage can extend: from a firstwork volume 109 (e.g., containing the X-ray scanner) at the entry of thesystem 100 to a last work volume 109 (e.g., containing the metalscanner) at the exit of the system 100.

However, the chassis 102 can define any other structure or arrangementof elements.

6.2 Sled

The sled rides on the linear sled stage and includes a set of clampsconfigured to receive and retain a recycled wood workpiece 115 during aprocessing cycle as the system 100 autonomously scans the recycled woodworkpiece 115 with the X-ray and optical scanners and then removesfasteners from the recycled wood workpiece 115.

In one implementation, the sled includes: a set of standoffs 108 thatrise above the stage to offset the recycled wood workpiece 115 above thestage and thus permit the scanners and fastener extractor modules tovisually access and remove fasteners from (most of) the surface of therecycled wood workpiece 115 facing the stage during the processingcycle; and an adjustable clamp arranged on each standoff and configuredto retain a section of the recycled wood workpiece 115 against itscorresponding standoff.

6.2.1 Sled Actuator+Sled Position Sensor

The sled actuator is configured to drive the sled—and the recycled woodworkpiece 115 clamped thereto—through the series of work volumes 109from the entry of the chassis 102 toward the exit of the chassis 102during a processing cycle.

In one implementation, the sled actuator includes a stepper or servomotor coupled to the linear sled stage via a belt or lead screw. In thisimplementation, the primary controller 160 can track the position of thesled—and therefore the recycled wood workpiece 115—along the linear sledstage based on angular rotations or positions of the stepper or servomotor.

In another implementation, the sled includes a linear encoder coupled toor integrated into the linear sled stage. In this implementation, theprimary controller 16 o can track or read the longitudinal position ofthe linear sled stage—and therefore the recycled wood workpiece115—within the system 100 from this linear encoder.

6.3 X-Ray Scanner

The X-ray scanner is arranged on the chassis 102 proximal the entry ofthe chassis 102 and is configured to capture a sequence of X-ray scandata of the recycled wood workpiece 115 at the sled as the sled actuatordrives the recycled wood workpiece 115 past the X-ray scanner during afirst segment of the processing cycle.

In one implementation, the X-ray scanner includes a one-dimensionalX-ray line scanner arranged over (or facing laterally across) the linearsled stage between the entry of the chassis 102 and the optical scanner.In this implementation, the X-ray scanner can capture a series of X-rayline scans of the recycled wood workpiece 115 as the sled actuatordrives the sled and the recycled wood workpiece 115 forward past theX-ray scanner. The primary controller 160 can then compile these X-rayline scans—based on cotemporal positions of the sled on the linear sledstage—into a two-dimensional X-ray scan of the recycled wood workpiece115.

In another implementation, the X-ray scanner includes: a one-dimensionalX-ray line scanner; and an X-ray stage configured to sweep the X-rayscanner between a position located over and a position facing laterallyacross the linear sled stage. In this implementation, the X-ray scannercan capture a first series of X-ray line scans through a sagittal axisof the recycled wood workpiece 115 and a second series of X-ray linescans through a lateral axis of the recycled wood workpiece 115 as thesled actuator drives the sled and the recycled wood workpiece 115forward past the X-ray scanner. The primary controller 160 can thencompile these X-ray line scans—based on cotemporal positions of the sledon the linear sled stage—into a three-dimensional X-ray scan of therecycled wood workpiece 115.

In a similar implementation, the X-ray scanner includes: a firstone-dimensional X-ray line scanner arranged over the linear sled stagebetween the entry of the chassis 102 and the optical scanner; and asecond one-dimensional X-ray line scanner arranged facing laterallyacross the linear sled stage between the entry of the chassis 102 andthe optical scanner. In this implementation, the X-ray scanner cancapture: a first series of X-ray line scans through a sagittal axis ofthe recycled wood workpiece 115 via the first X-ray scanner; and asecond series of X-ray line scans through a lateral axis of the recycledwood workpiece 115 via the second X-ray scanner. The primary controller160 can then compile these X-ray line scans—based on cotemporalpositions of the sled on the linear sled stage—into a three-dimensionalX-ray scan of the recycled wood workpiece 115.

In the foregoing implementations, the X-ray scanner can alternativelyinclude a two-dimensional X-ray scanner, and the primary controller 160can implement similar methods and techniques to stitch two-dimensionalX-ray scans—captured by the X-ray scanner—into a two- orthree-dimensional X-ray scan of the recycled wood workpiece 115.

6.4 Optical Scan Module

The optical scan module is similarly arranged proximal the X-ray scanneropposite the entry of the chassis 102 and is configured to capture asequence of optical scan data of the recycled wood workpiece 115 duringa second segment of the processing cycle following the first segment ofthe processing cycle.

In one implementation, the optical scan module includes aone-dimensional color (e.g., RGB, multispectral) line scanner arrangedover (or facing laterally across) the linear sled stage between theentry of the chassis 102 and the optical scanner. In thisimplementation, the optical scan module can capture a series of opticalline scans of the recycled wood workpiece 115 as the sled drives thesled and the recycled wood workpiece 115 forward past the opticalscanner. The primary controller 160 can then compile these optical linescans—based on cotemporal positions of the sled on the linear sledstage—into a two-dimensional optical scan of the recycled wood workpiece115.

In another implementation, the optical scan module includes: aone-dimensional color line scanner; and an optical stage configured tosweep the optical scanner between a position located over and a positionfacing laterally across the linear sled stage. In this implementation,the optical scan module can capture a first series of optical line scansthrough a sagittal axis of the recycled wood workpiece 115 and a secondseries of optical line scans through a lateral axis of the recycled woodworkpiece 115 as the sled drives the sled and the recycled woodworkpiece 115 forward past the optical scanner. The primary controller160 can then compile these optical line scans—based on cotemporalpositions of the sled on the linear sled stage—into a three-dimensionaloptical scan of the recycled wood workpiece 115.

In a similar implementation, the optical scan module includes: a firstone-dimensional color line scanner arranged over the linear sled stagebetween the entry of the chassis 102 and the optical scanner; and asecond one-dimensional optical line scanner arranged facing laterallyacross the linear sled stage between the entry of the chassis 102 andthe optical scanner. In this implementation, the optical scan module cancapture: a first series of optical line scans through a sagittal axis ofthe recycled wood workpiece 115 via the first optical scanner; and asecond series of optical line scans through a lateral axis of therecycled wood workpiece 115 via the second optical scanner. The primarycontroller 160 can then compile these optical line scans—based oncotemporal positions of the sled on the linear sled stage—into athree-dimensional optical scan of the recycled wood workpiece 115.

In the foregoing implementations, the optical scan module canadditionally or alternatively include: a structured light camera(configured to output RGB-D depth maps and point clouds); atwo-dimensional color or hyperspectral camera; a stereoscopic colorcamera; a depth camera; and/or a thermographic camera; etc. The primarycontroller 160 can implement similar methods and techniques to stitchthese two- and/or three-dimensional optical scans—captured by theoptical scanner—into a two- or three-dimensional virtual representationof the recycled wood workpiece 115 (e.g., a “virtual model”).

6.5 Fastener Extractor Modules

In this variation, the system 100 also includes a set of fastenerextractor modules, each: mounted to the exo-structure between theoptical scanner and the exit of the chassis 102; including an endeffector configured to engage a fastener on the recycled wood workpiece115; and including a set of actuators configured to manipulate the endeffector, on the exo-structure of the chassis 102, to retract thefastener from the recycled wood workpiece 115 during a third segment ofthe processing cycle.

In particular, each fastener extractor module: is configured to mountwithin a work zone defined by the chassis 102; includes an end effectorconfigured to engage a particular type of fastener (e.g., a screw, anail, a staple); and configured to navigate the endeffector—independently of the other fastener extractor modules—to targetand remove fasteners of a corresponding type in a segment of therecycled wood workpiece 115 occupying the same work volume 109, asfurther described below.

6.6 System Configuration

In one configuration, the chassis 102 and the sled: are configured toretain and manipulate a single recycled wood workpiece 115 up to 30 feetin length, two recycled wood workpieces 115 up to 15 feet in length, orthree recycled wood workpieces 115 up to 10 feet in length, etc.; andinclude an arrangement of clamps to retain such combinations of recycledwood workpiece 115 lengths. In this implementation, the primarycontroller 160 executes processes described below for each recycled woodworkpiece 115 concurrently located on the sled during one processingcycle.

In this configuration, the system 100 can include a series of eight workvolumes 109 behind the X-ray scanner, including: a first row of fourthreaded fastener (e.g., screws) removal modules arranged overhead thelinear sled stage, each exhibiting an actuation radius of 3 feet overthe linear sled stage; a first row of four non-threaded fastener (e.g.,nails, staples) removal modules arranged overhead the linear sled stage,interposed between the four threaded fastener extractor modules 130, andeach exhibiting an actuation radius of 3 feet over the linear sledstage; and similar rows of interleaved threaded fastener (e.g., screw)extractor modules 130 and non-threaded fastener (e.g., nails, staples)extractor modules 120 to the left of, to the right of, and under thelinear sled stage.

However, the system 100 can define a series of work volumes 109supporting any other arrangement of scanners and fastener extractormodules of any other size and/or configured to process recycled woodworkpieces 115 or other wood products in any other size or format.

6.7 Processing Cycle

In this variation, at the start of a processing cycle, the primarycontroller 160 resets the sled to a home position at the entry of thechassis 102. An human operator or a machine (e.g., forklift) then loadsa recycled wood workpiece 115 onto the sled and clamps the recycled woodworkpiece 115 to the sled. Alternatively, once the recycled woodworkpiece 115 is placed on the sled, the primary controller 160 canautomatically trigger the clamps to close onto the recycled woodworkpiece 115. The primary controller 16 o then implements methods andtechniques described above to initiate the processing cycle.

6.7.1 Processing Cycle: Initial Imaging

The primary controller 160 then: triggers the sled actuator to drive thesled forward along the X-ray and optical scan modules; tracks theposition of the sled relative to the X-ray and optical scan modules; andcollects a series of X-ray and optical (e.g., color, depth) images ofthe recycled wood workpiece 115 from sensors arranged within thesemodules as the recycled wood workpiece 115 passes through the field ofview of each sensor.

6.7.2 Processing Cycle: Virtual Model

The primary controller 160 then compiles this series of optical scandata into a three-dimensional representation (or “virtual model”) of therecycled wood workpiece 115, such as depicting: external surfaces (e.g.,top, bottom, front, back, left, and right external surfaces) of therecycled wood workpiece 115; and volumetric representations of fastenersthat extend above the external surfaces of the recycled wood workpiece115.

In one implementation, the primary controller 160 implements imagestitching techniques to assemble depth and color images—captured by theoptical scanner—and concurrent positions of the sled into a “virtualmodel.”

In one variation, the primary controller 160 further projects the X-rayscan data onto the three-dimensional representation of the recycled woodworkpiece 115 to populate the virtual model with internal features anddefects of the recycled wood workpiece 115. In one implementation inwhich the X-ray scanner defines a fixed line or two-dimensional scannerfacing a single side of the sled (e.g., arranged over and facingdownward toward the sled), the system 100 can: compile the sequence ofX-ray scan data into a two-dimensional representation of internalfeatures (i.e., defects) in the recycled wood workpiece 115—projectedonto a plane normal to the focal axis of the X-ray scanner; and projectthe two-dimensional representation of internal features in the recycledwood workpiece 115 onto the three-dimensional representation of therecycled wood workpiece 115.

In another implementation in which the X-ray scanner includes two fixedperpendicular line scanners or an X-ray scanner that sweeps across twoaxes perpendicular to the sled as the sled advances the recycled woodworkpiece 115 toward the first fastener extractor module, the system 100can: compile the sequence of X-ray scan data captured by these X-rayscanners into a three-dimensional representation of internal features(i.e., defects) in the recycled wood workpiece 115; and align and insertthe three-dimensional representation of internal features in therecycled wood workpiece 115 into the three-dimensional representation ofthe recycled wood workpiece 115.

However, the primary controller 160 can implement any other method ortechnique to generate a representation of the exterior surfaces of therecycled wood workpiece 115 based on X-ray and/or optical scan datacollected by the X-ray scanner and optical sensors 110.

6.8 Fastener Removal Schedule

Therefore, the primary controller 160 can execute the foregoing methodsand techniques to: generate a virtual model representing internal and/orexternal features of the recycled wood workpiece 115; detect locations,orientations, and types of fasteners on the recycled wood workpiece 115;characterize quality of the recycled wood workpiece 115; identifysegments of the recycled wood workpiece 115 to discard; and annotate thevirtual model with cut locations for discarding recycled wood workpiece115 segments and removing fasteners.

In one configuration of the system 100 described above, the system 100includes a series of operating modules behind the X-ray scanner,including: a row of threaded fastener (e.g., screw) removal modules,interposed with non-threaded fastener extractor modules 120, and eachexhibiting an actuation radius of 3 feet overhead the linear sled stage;and a similar set of threaded fastener (e.g., screw) removal modules,interposed with non-threaded fastener extractor modules 120, on the leftside of, on the right side of, and under the linear sled stage.

In this configuration, the primary controller 160 can initialize afastener removal schedule. The primary controller 160 can also calculatea first sled position that: locates a trailing end of the recycled woodworkpiece 115 under (or near) a first column of threaded fastenerextractor modules 130 arranged about the sled within a thresholddistance of the optical scanner; and locates a leading end of therecycled wood workpiece 115 under (or near) a last column of threadedfastener extractor modules 130 arranged about the sled near the exit ofthe system 100. The primary controller 160 similarly: calculates arecycled wood workpiece 115 offset between a coordinate system of therecycled wood workpiece 115—assigned in the recycled wood workpiece 115module—and a global coordinate system of the system 100 when the sledadvances to a first sled position; and writes a first code—to move thesled to the first sled position—to the fastener removal schedule.

The primary controller 160 then assigns: removal of flagged screws in atop surface of a first segment of the recycled wood workpiece 115 to thefirst threaded fastener extractor module 130 above the sled; removal offlagged screws in the top surface of a second segment of the recycledwood workpiece 115 to a second threaded fastener extractor module 130above the sled; removal of flagged screws in the top surface of a thirdsegment of the recycled wood workpiece 115 to a third threaded fastenerextractor module 130 above the sled; removal of flagged screws in theleft surface of the first segment of the recycled wood workpiece 115 toa first threaded fastener extractor module 130 left of the sled; andremoval of flagged screws in the bottom surface of the fourth segment ofthe recycled wood workpiece 115 to a fourth threaded fastener extractormodule 130 below the sled.

For a first flagged screw in the top surface of the first segment of therecycled wood workpiece 115 assigned to the first threaded fastenerextractor module 130 over the linear sled stage, the primary controller160 can calculate a position and orientation of the first screw in afirst extractor coordinate system of the first threaded fastenerextractor module 130 based on: a position (of the head of) andorientation of the first screw in the coordinate system of the virtualmodel; the offset between the recycled wood workpiece 115 coordinatesystem and the global coordinate system in the first sled position; andthe offset between the recycled wood workpiece 115 coordinate system andthe first extractor coordinate system. The primary controller 160 canthen: locate a first predefined (or “canned”) threaded fastener removalcycle relative to the position (of the head of) and orientation of thefirst screw in the first extractor coordinate system; and assign thisfirst predefined threaded fastener removal cycle to the first threadedfastener extractor module 130 when the sled occupies the first sledposition.

The primary controller 160 can repeat this process for each otherflagged screw in the top surface of the first segment of the recycledwood workpiece 115 assigned to the first threaded fastener extractormodule 130.

The primary controller 160 can then: sort or order the correspondingthreaded fastener removal cycles from nearest the entry of the system100 to the exit (or vice versa); write codes for this batch of threadedfastener removal cycles, assigned to the first threaded fastenerextractor module 130, to the fastener removal schedule; and repeat thisprocess to calculate and order threaded fastener removal cycles forgroups of flagged fasteners in each other segment and side of therecycled wood workpiece 115 relative to coordinate systems of theircorresponding threaded fastener extractor modules 130.

In this configuration, the primary controller 160 can then calculate asecond sled position that: locates a trailing end of the recycled woodworkpiece 115 under (or near) a first column of non-threaded fastenerextractor modules 120 arranged about the sled just aft of the opticalscanner; and locates a leading end of the recycled wood workpiece 115under (or near) a last column of non-threaded fastener extractor modules120 arranged about the sled near the exit of the system 100. The primarycontroller 160 can then: calculate a recycled wood workpiece 115 offsetbetween a coordinate system of the recycled wood workpiece 115—assignedin the recycled wood workpiece 115 module—and a global coordinate systemof the system 100 when the sled advances to the second sled position;and write a second code—to move the sled to the second sled position—tothe fastener removal schedule.

Accordingly, the primary controller 160 can assign: removal of flaggednails and/or staples in a top surface of the first segment of therecycled wood workpiece 115 to the first non-threaded fastener extractormodule 120 above the sled; removal of flagged nails and/or staples inthe top surface of the second segment of the recycled wood workpiece 115to a second non-threaded fastener extractor module 120 above the sled;removal of flagged nails and/or staples in the top surface of the thirdsegment of the recycled wood workpiece 115 to a third non-threadedfastener extractor module 120 above the sled; . . . removal of flaggednails and/or staples in the left surface of the first segment of therecycled wood workpiece 115 to a first non-threaded fastener extractormodule 120 left of the sled; . . . and removal of flagged nails and/orstaples in the bottom surface of the fourth segment of the recycled woodworkpiece 115 to a fourth non-threaded fastener extractor module 120below the sled.

For a first flagged nail and/or staple in the top surface of the firstsegment of the recycled wood workpiece 115 assigned to the first nailextraction module over the linear sled stage, the primary controller 160can calculate a position and orientation of the first nail and/or staplein a first extractor coordinate system of the first non-threadedfastener extraction module based on: a position (e.g., of the head of anail, a connecting segment and/or leg of a staple) and orientation ofthe first nail and/or staple in the coordinate system of the virtualmodel; the offset between the recycled wood workpiece 115 coordinatesystem and the global coordinate system in the second sled position; andthe offset between the recycled wood workpiece 115 coordinate system andthe first extractor coordinate system. Accordingly, the primarycontroller 160 can locate a first predefined (or “canned”) nail and/orstaple extraction cycle relative to the position (of the head of a nail,a connecting segment and/or leg of a staple) and orientation of thefirst nail and/or staple in the first extractor coordinate system; andassign this first predefined nail and/or staple extraction cycle to thefirst non-threaded fastener module when the sled occupies the first sledposition.

The primary controller 160 can repeat this process for each otherflagged nail and/or staple in the top surface of the first segment ofthe recycled wood workpiece 115 assigned to the first non-threadedfastener extraction module.

The primary controller 160 can then: sort or order the correspondingnail and/or staple extraction cycles from nearest the entry of thesystem 100 to the exit (or vice versa); write codes for this batch ofnail and/or staple extraction cycles, assigned to the first non-threadedfastener extraction module, to the fastener removal schedule; and repeatthis process to calculate and order nail and/or staple extraction cyclesfor groups of flagged fasteners in each other segment and side of therecycled wood workpiece 115 relative to coordinate systems of theircorresponding non-threaded fastener extraction modules.

Therefore, in this configuration, the primary controller 160 can defineand order threaded fastener removal cycles simultaneously executable byup to sixteen threaded fastener extractor modules 130 arranged about thelinear sled stage to remove all accessible (e.g., superficial) screwsfrom the recycled wood workpiece 115 while the recycled wood workpiece115 and linear sled stage occupy the first sled positions. Similarly,the primary controller 160 can define and order nail and/or stapleextraction cycles simultaneously executable by up to sixteennon-threaded fastener extractor modules 120 arranged about the linearsled stage to remove all accessible (e.g., superficial) nails and/orstaples from the recycled wood workpiece 115 while the recycled woodworkpiece 115 and linear sled stage occupy the second sled positions.

The primary controller 160 can implement similar methods and techniquesto define cut paths for one or more saws mounted to the chassis 102 ormark lines for one or more cut marking modules mounted to the chassis102.

Alternatively, the primary controller 160 can: coordinate simultaneousremoval of fasteners by threaded fastener and non-threaded fastenerextractor modules 120; and/or coordinate multiple advancements of thesled to locate segments of the recycled wood workpiece 115 in particularwork volumes 109 for fastener removal by threaded fastener and/ornon-threaded fastener extractor modules 120 mounted in these workvolumes 109. The primary controller 160 can then compile these moves andextraction cycles into the fastener removal schedule.

7. Non-Threaded Fastener Extractor Module

As described above, the system 100 can include a set of non-threadedfastener extractor modules 120 for removing non-threaded fastenersembedded within and/or extending above a recycled wood workpiece 115.Each non-threaded fastener extractor module 120 includes: a multi-axisstage 121; a non-threaded fastener end effector 122; a set of moduleactuators; and a local controller 170.

7.1 Gantry and Actuators

In one implementation, the multi-axis stage 121 includes a three-axisgantry (e.g., X-, Y-, and Z-axes): supported by the chassis 102;arranged in a work volume 109 over a section of the linear sled stage;configured to face (e.g., is arranged over, under, or adjacent) one sideof a recycled wood workpiece 115 loaded onto the sled; and configured tosupport the non-threaded fastener end effector 122 over a range ofvertical, lateral, and longitudinal positions to enable the non-threadedfastener end effector 122 to access non-threaded fasteners (e.g., nails,staples) in a range of positions and orientations on an adjacent side ofthe recycled wood workpiece 115.

In this implementation, a set of actuators can include a set of stepperor servo motors coupled to and configured to independently actuate eachaxis of the stage 121, such as via a belt or leadscrew. Furthermore, thenon-threaded fastener extractor module 120 can include a set of positionsensors—such as rotary or linear encoders coupled to the set ofactuators or directly to the stage 121, respectively of eachnon-threaded fastener extractor module 120. The local controller 170 cantrack the position of each axis of the stage 121 via these positionsensors and interpolate the three-dimensional position of thenon-threaded fastener end effector 122—mounted to the third axis of thegantry—within the work volume 109 based on the combined positions ofthese axes of the stage 121.

For example, the three-axis gantry is arranged in the work volume 109and facing a first side of the recycled wood workpiece 115 loaded ontothe conveyor 105. A position sensor is mounted to the three-axis gantryand configured to output signals representing positions of thethree-axis gantry. In this example, the local controller 170 can then:interpret a set of positions of the three-axis gantry based on positionsof the three-axis gantry detected by the position sensor; andinterpolate a three-dimensional position—such as a surge position, aheave position, and a sway position (e.g., (x,y,z) position within thecoordinate system of the non-threaded fastener extractor module 120)—ofthe non-threaded fastener end effector 122 within the work volume 109based on the set of positions.

In another implementation, the stage 121 includes a robotic arm, such asa three-link robotic arm with base rigidly mounted to the chassis 102and configured to reach the full length and width of the near side of asegment of a recycled wood workpiece 115 occupying the work volume 109.In this implementation, the set of actuators are configured tomanipulate joints between the base and links of the robotic arm.

In a similar implementation, the stage 121 includes: a single-axisgantry arranged over (or adjacent, under) and parallel to the linearsled stage; and a two-link robotic arm mounted to the gantry andconfigured to cooperate with the gantry to reach the full length andwidth of the near side of a segment of a recycled wood workpiece 115occupying the work volume 109. In this implementation, the set ofactuators are configured to manipulate the gantry and joints betweenlinks of the robotic arm to reach the non-threaded fastener end effector122 throughout the scope of the work volume 109.

Furthermore, the non-threaded fastener extractor module 120 can includea set of position sensors—such as linear or rotary encoders—coupled tojoints of the robotic arm and/or to axes of the gantry of eachnon-threaded fastener extractor module 120. The local controller 170 cantrack the position of the distal end of the robotic arm—and therefore,the non-threaded fastener end effector 122—within the work volume 109based on the positions of joints of the robotic arm and the position ofthe gantry within the work volume 109.

However, the multi-axis stage 121 can define any other configuration orarrangement of actuators and supporting structures.

7.2 Non-Threaded Fastener End Effector

As described above, the non-threaded fastener end effector 122 issupported by the multi-axis stage 121 and includes: a bearing plate 123;a vertical stage 124 arranged on the multi-axis stage 121 and configuredto advance the bearing plate 123 toward a non-threaded fastener in arecycled wood workpiece 115 occupying the work volume 109 and to retractthe bearing plate 123 to withdraw the non-threaded fastener from therecycled wood workpiece 115; a jaw head 126 arranged on and rotationallycoupled to a distal face of the bearing plate 123; a set of jaws 128pivotably coupled to a distal end of the jaw head 126; a yaw actuator127 arranged on the bearing plate 123; and a jaw actuator 125 arrangedon the vertical stage 124, coupled to the set of jaws 128 via a jawlinking and configured to close the set of jaws 128 to engage the set ofjaws 128 against the non-threaded fastener and to open the set of jaws128 to release the non-threaded fastener from the set of jaws 128.

7.2.1 Vertical Stage

In one implementation, the vertical stage 124: is pivotably coupled to adistal end of the multi-axis stage 121; defines a jaw actuator mountconfigured to support and locate the jaw actuator 125; and includes aset of fixed standoffs 108 concentric with a W-axis of the jaws 128, theset of fixed standoffs 108 configured to receive a set of fixed rods.The set of fixed rods define distal ends pivotably coupled to the set offixed standoffs 108 and proximal ends coupled to the bearing plate 123.The vertical stage 124 is also configured to support a bearing plate123, advance the bearing plate 123 toward a non-threaded fastener in arecycled wood workpiece 115 occupying the work volume 109, and retractthe bearing plate 123 to withdraw the non-threaded fastener from therecycled wood workpiece 115.

7.2.2 Jaw Actuator

The non-threaded fastener end effector 122 can include anelectromechanical, pneumatic, or hydraulic jaw actuator 125: arranged onthe vertical stage 124; coupled to the set of jaws 128 via a jaw linkingincluding a gear; and configured to close the set of jaws 128 to engagethe set of jaws 128 against the non-threaded fastener and to open theset of jaws 128 to release the non-threaded fastener from the set ofjaws 128.

7.2.3 Bearing Plate+Yaw Actuator+Jaw Head

The bearing plate 123 includes: a proximal face configured to fastendistal ends of the set of fixed standoffs 108 and a distal end of thejaw actuator 125 to mount the jaw actuator 125 to the bearing plate 123;and a distal face opposite the proximal face. The jaw head 126 isrotationally coupled to the distal face of the bearing plate 123 via athrust-bearing, the thrust-bearing configured to transfer a rotationalforce into the jaw head 126 to rotate the set of jaws 128 (e.g., Y-axisrotation, yaw) to a target orientation with no or minimal torque.

The yaw actuator 127 is arranged on the proximal face of the bearingplate 123, coupled to the jaw head 126, and configured to rotate the jawhead 126 about a yaw axis of the non-threaded fastener end effector 122.

7.2.4 Thrust Bearing+Gear

The non-threaded extractor end effector can also include a thrustbearing: interposed between the jaw head 126 and the set of jaws 128 ofthe non-threaded fastener end effector 122. The non-threaded fastenerend effector 122 can also include a gear interposed between the distalface of the bearing plate 123 and the jaw head 126.

7.2.5 Jaws

The non-threaded fastener end effector 122 also includes a set of (e.g.,two, three) jaws 128, each jaw 128 coupled to the jaw head 126 via a setof jaw pivots. The set of jaws 128 are operable in: a closed position toclamp against and retain a shaft and/or shank of a non-threaded fastenerand to transfer a force into the non-threaded fastener to retract thenon-threaded fastener from a recycled wood workpiece 115 during anon-threaded fastener removal cycle; and an open position to release thenon-threaded fastener, such as into a fastener container 145 followingcompletion of the non-threaded fastener removal cycle.

For example, each jaw 128 can include a hardened steel jaw 128 with asharpened jaw surface configured to engage and retain a shaft and/orshank of a non-threaded fastener flush with a surface of a recycled woodworkpiece 115, extending above the surface of the recycled woodworkpiece 115, and/or extending below the surface of the recycled woodworkpiece 115.

Therefore, at the start of a non-threaded fastener removal cycle, thelocal controller 170 can: autonomously navigate the non-threadedfastener end effector 122 to a target engagement position, via themulti-axis stage 121, and a target jaw position, via the yaw actuator127, predicted by the local controller 170 to contain a shaft and/orshank of a non-threaded fastener. The vertical stage 124 can thenadvance the bearing plate 123 toward the non-threaded fastener in arecycled wood workpiece 115 occupying the work volume 109. The jawactuator 125 can close the set of jaws 128 to engage the set of jaws 128against the non-threaded fastener with a target clamping force and toopen the set of jaws 128 to release the non-threaded fastener from theset of jaws 128. Upon completion of the non-threaded fastener retractioncycle, the vertical stage 124 can retract the bearing plate 123 towardthe vertical stage 124 and open the set of jaws 128 to release thenon-threaded fastener from the set of jaws 128 into a fastener container145 at the end of the non-threaded fastener removal cycle.

7.3 W-Axis Home Position

In one implementation, the vertical stage 124: is mounted to the distalend of the multi-axis stage 121 via a linear slide; and is operable overa range of linear positions on the linear slide parallel to a W-axis ofrotation of the jaws 128.

For example, the jaw actuator 125 can include a pneumatic piston coupledto a pressure reservoir and an exhaust via a set of valves. At the startof a non-threaded fastener removal cycle, the local controller 170:activates a first valve to supply pressurized air to the jaw actuator125, which drives the jaw actuator 125 forward on the linear slide tostop at maximum extension; triggers the set of jaws 128 to close; andthen closes the first valve and opens a second value to enable air inthe jaw actuator 125 to vent to ambient, thereby reducing or eliminatingforward force on the set of jaws 128. The local controller 170 can thenactivate the jaw actuator 125 to retract the bearing plate 123 towardthe vertical stage 124 and the set of jaws 128 engaged with anon-threaded fastener—the latter of which backs out of the recycled woodworkpiece 115 and thus drives the bearing plate 123 up the verticalstage 124.

The non-threaded fastener end effector 122 can also include a linearencoder, a set of home switches, or other position sensors coupled tothe jaw actuator 125, the vertical stage 124, the jaw head 126, or theset of jaws 128. During a non-threaded fastener extraction cycle, thelocal controller 170 can: track the position of the jaw actuator 125 onthe vertical stage 124 via the position sensor; track an offset distancebetween the jaws 128 during a non-threaded fastener removal cycle anddetect extraction of a non-threaded fastener from a recycled woodworkpiece 115 based on retraction of the bearing plate 123 to withdrawthe non-threaded fastener from the recycled wood workpiece 115; detectremoval of a non-threaded fastener (or failure of the non-threadedfastener) from a recycled wood workpiece 115 based on retraction of thebearing plate 123 toward the vertical stage 124 followed by the bearingplate 123 reaching a static linear position on the vertical stage 124(and based on minimal or no load on the jaw actuator); and/or detect jawslippage on a non-threaded fastener or inadvertent engagement of athreaded fastener based on absence of retraction of the bearing plate123 toward the vertical stage 124 based on low load on the jaw actuator125 and/or based on an offset distance between the set of jaws128—detected by the linear position sensor—falling below an offsetdistance threshold.

In one implementation, the non-threaded fastener end effector 122 caninclude: a force sensor coupled to the set of jaws 128 and configured tooutput a first signal corresponding to a clamping force of the set ofjaws 128; and a position sensor coupled to the jaw actuator 125, facingthe set of jaws 128, and configured to output a second signalcorresponding to an offset distance between each jaw 128 in the set ofjaws 128. In this implementation, the local controller 170 can:interpret a first clamping force of the set of jaws 128 based on thefirst signal; interpret a first offset distance between each jaw 128 inthe set of jaws 128 based on the second signal; and identify engagementof the set of jaws 128 with the fastener in the section of the recycledwood workpiece 115, in response to the first clamping force fallingbelow a clamping force threshold and in response to the first offsetdistance exceeding an offset distance threshold.

Alternatively, the force sensor is configured to output a third signalcorresponding to the clamping force of the set of jaws 128 and theposition sensor is configured to output a fourth signal corresponding tothe offset distance between each jaw 128 in the set of jaws 128. Thelocal controller 170 can then: interpret a second clamping force of theset of jaws 128 based on the third signal; interpret a second offsetdistance between each jaw 128 in the set of jaws 128 based on the fourthsignal; and identify jaw slippage of the set of jaws 128 with thefastener in the section of the recycled wood workpiece 115, in responseto the first clamping force falling below the clamping force thresholdand in response to the first offset distance falling below the offsetdistance threshold.

7.4 Non-Threaded Fastener Extractor Module: Degrees of Freedom

As described above, the multi-axis stage 121 is operable in threedegrees of freedom to locate the non-threaded fastener end effector 122over a range of positions within the work volume 109. The non-threadedfastener end effector 122 is pivotably coupled to the distal end of themulti-axis gantry via the vertical stage 124. Accordingly, the localcontroller 170 can drive the multi-axis stage 121 and the yaw actuator127 to locate the jaws 128 adjacent (e.g., spanning) the shaft and/orshank of a non-threaded fastener protruding above a side of a recycledwood workpiece 115.

Furthermore, the non-threaded fastener end effector 122 can include ayaw actuator 127 to trigger a gear to transfer a rotational force torotate the jaw head 126 and the set of jaws 128 (e.g., Y-axis rotation,yaw) according to a target orientation. The yaw actuator 127 thusdefines a further degree of freedom of the non-threaded fastener endeffector 122. Additionally, the non-threaded fastener end effector 122includes a jaw actuator 125 configured to open and close the jaws 128independently of the rotation of the jaws 128, and thus defines yetanother degree of freedom of the non-threaded fastener end effector 122.Accordingly, the local controller 170 can actuate the jaw actuator 125to clamp the jaws 128 against a non-threaded fastener extending above anadjacent side of the recycled wood workpiece 115.

Therefore, the multi-axis stage can support and locate the non-threadedfastener end effector 122 in three degrees of freedom. The jaw actuatorlocates the jaws in a translational degree of freedom (e.g., heave) andthe yaw actuator 127 in a further rotational degree of freedom (e.g.,yaw). Thus, the non-threaded fastener end effector 122 can support andlocate the jaws 128 in five degrees of freedom.

However, the elements of the non-threaded fastener end effector 122described above can be arranged in any other configuration to similarlysupport and locate the jaws in five degrees of freedom.

7.5 Non-Threaded Fastener Removal Cycle

In one implementation, once a section of a recycled wood workpiece 115enters a work volume 109 of a non-threaded fastener extractor module120, the local controller 170 calculates a position and predictedorientation of a non-threaded fastener—on the section of the recycledwood workpiece 115 (e.g., super surface, flush with the surface of therecycled wood workpiece 115, subsurface)—within a local coordinatesystem of the non-threaded fastener extractor module 120 based on: theposition of the non-threaded fastener within the coordinate system ofthe virtual model; the predicted orientation of the non-threadedfastener, within the coordinate system of the virtual model, derivedfrom the virtual model; the longitudinal position of the section of therecycled wood workpiece 115 within a global coordinate system of thesystem Dm; and/or a known or stored position of the local coordinatesystem of the non-threaded fastener extractor module 120 relative to theglobal coordinate system. The local controller 170 also triggers the jawactuator to fully advance and open the set of jaws.

Additionally, the local controller 170 can: interpolate the position ofthe set of jaws 128 and the orientation of the set of jaws 128 of thenon-threaded fastener extractor module 120 within the local coordinatesystem based on positions of the multi-axis stage 121, the linear stage,etc. and based on an orientation of the gear; and autonomously navigatethe multi-axis stage 121 and the gear to locate the set of jaws 128adjacent (e.g., spanning) a segment of the non-threaded fastenerextending above the adjacent surface of the recycled wood workpiece 115and to locate the W-axis of the set of jaws 128 coaxial with thepredicted orientation of the non-threaded fastener.

The local controller 170 can then: trigger the jaw actuator 125 to closethe jaws 128, thereby clamping the jaws 128 onto the non-threadedfastener; and trigger the vertical stage 124 to retract the bearingplate 123, thereby extracting the non-threaded fastener from therecycled wood workpiece 115.

Furthermore, during this non-threaded fastener extraction cycle and asdescribed above, the local controller 170 can: actuate the verticalstage 124 to bias (or “preload”) the set of jaws 128 and the jawactuator 125 away from the recycled wood workpiece 115 and thus maintaina continuous retraction force on the non-threaded fastener; track theposition and offset distance of the set of jaws 128 via a linearposition sensor; verify extraction of the non-threaded fastener from therecycled wood workpiece 115 responsive to retraction of the bearingplate 123 toward the vertical stage 124; and detect removal of thenon-threaded fastener from the recycled wood workpiece 115 (or failureof the non-threaded fastener) responsive to subsequent cessation orretraction of the bearing plate 123 toward the vertical stage 124. Upondetecting removal (or failure) of the non-threaded fastener, the localcontroller 170 can: autonomously navigate the multi-axis stage 121 tolocate the set of jaws 128 over the fastener container 145; trigger thejaw actuator 125 to open the set of jaws 128, thereby releasing thenon-threaded fastener into the fastener container 145; verify removal ofthe non-threaded fastener in response to detecting an object passing thebreak beam or motion sensor on the fastener container 145 within athreshold duration (e.g., one second) after triggering the jaw actuator125 to open the set of jaws 128; and record removal of the non-threadedfastener from the recycled wood workpiece 115, such as by annotating arepresentation of the non-threaded fastener in the virtual model with a“removed” flag.

The non-threaded fastener extractor module 120 can repeat this processfor each other non-threaded fastener detected on the adjacent side ofthe recycled wood workpiece 115 occupying the work volume 109.

7.5.1 Superficial Straight Nail Removal Cycle

In one implementation, the local controller 170 can identify a straightnail normal to the surface of a recycled wood workpiece 115 occupyingthe work volume 109 and superficial to the recycled wood workpiece 115(e.g., protruding above the surface of the of recycled wood workpiece115) based on an image of the work volume 109 captured by the opticalsensor 110.

For example, the local controller 170 can: detect a straight nailsuperficial to a surface of section of the recycled wood workpiece 115based on features extracted from the image; detect a shank axis and anintersection of a shank and a nail head of the straight nail based onthe features; trigger the stage (e.g., multi-axis stage 121) to drivethe non-threaded fastener end effector 122 to a target engagementposition to align the retraction axis of the set of jaws 128 coaxialwith the axis of the straight nail; trigger the jaw actuator 125 toengage the straight nail at the intersection of the shank and the nailhead (e.g., close the set of jaws 128 against the straight nail with atarget clamping force, at the intersection of the shank and the nailhead); trigger the stage (e.g., vertical stage 124) to retract thenon-threaded fastener end effector 122 from the target engagementposition to extract the straight nail from the recycled wood workpiece115; and trigger the jaw actuator 125 to open the set of jaws 128 torelease the straight nail into a fastener container 145.

Similarly, the local controller 170 can: extract a breadth of the nailhead based on the features; calculate a centroid of the nail head basedon the breadth; derive a target jaw position to locate the retractionaxis of the set of jaws 128 coaxial with the centroid of the nail head;and trigger the jaw actuator 125 to open the set of jaws 128 by adistance proportional to the breadth of the head of the fastener, inresponse to driving the non-threaded fastener end effector 122 to thetarget engagement position. The local controller 170 can then implementmethods and techniques described above to extract the straight nail fromthe recycled wood workpiece 115.

In another implementation, the local controller 170 can identify asecond straight nail non-normal to the surface (e.g., angularly offset)of a recycled wood workpiece 115 occupying the work volume 109 andsuperficial to the recycled wood workpiece 115 (e.g., protruding abovethe surface of the of recycled wood workpiece 115) based on X-rayimages. The local controller 170 can then: identify an engagement pointat the entry of the shank of the second straight nail into the recycledwood workpiece 115; derive a shank axis of the second straight nailrelative the recycled wood workpiece 115 based on the engagement point;calculate a target orientation for the set of jaws 128 based on theangular offset of the second straight nail; autonomously navigate themulti-axis stage 121 to align the retraction axis of the set of jaws 128coaxial with the shank axis of the second straight nail; trigger the yawactuator 127 to rotate the jaws 128 about the yaw axis of thenon-threaded fastener end effector 122 to the target orientation;trigger the jaw actuator 125 to drive the set of jaws 128 to theengagement point and to close the set of jaws 128 against the secondstraight nail with a target clamping force to extract the secondstraight nail; trigger the vertical stage 124 to retract the bearingplate 123; and trigger the jaw actuator 125 to open the set of jaws 128to release the second straight nail into a fastener container 145.

The local controller 170 can implement similar methods and techniques toremove each other straight nail normal and/or non-normal and superficial(e.g., protruding above the surface of the recycled wood workpiece 115)to each other recycled wood workpiece 115 occupying the work volume 109.

7.5.2 Subsurface+Flush Straight Nail Removal Cycle

Generally, the local controller 170 can implement the methods andtechniques described above to remove a nail extending below and/orembedded within a surface of the recycled wood workpiece 115 (e.g.,subsurface) and/or flush to the surface of the recycled wood workpiece115.

In one implementation, the local controller 170 can identify a straightnail extending below the surface and/or embedded within the section ofthe recycled wood workpiece 115 based on an image of the work volume 109captured by the optical sensor no. Then, the local controller 170 can:access a maximum jaw depth for removing a straight nail (e.g., 0.5inches); and calculate a target depth of the jaws 128 to engage a shankof the nail below the nail head, such as including plunging the jaws 128below the surface of the recycled wood workpiece 115 to clamp againstthe shank of the nail. In particular, in this implementation, the localcontroller 170 can calculate the target depth for the jaws 128 as afunction of a total length of the shank of the nail, such as a targetdepth corresponding to a distance below the nail head derived from anX-ray or color image of the recycled wood workpiece 115 and less thanthe maximum jaw depth.

In one variation, the local controller 170 can: access an image of thework volume 109 captured by the optical sensor 110 and identify afastener embedded in the surface of the recycled wood workpiece 115occupying the work volume 109 based on features extracted from theimage; extract a position and orientation of a head of the fastenerbased on the features; access the virtual model (e.g., three-dimensionalmodel) of the work volume 109 occupied by the recycled wood workpiece115 labeled with fastener types, positions, and orientations; scan thethree-dimensional model for a fastener; and identify the fastener in thevirtual model labeled with a nail fastener type based on the positionand the orientation of the head of the fastener. The local controller170 can then identify the fastener embedded in the section of therecycled wood workpiece 115 as a nail and implement methods andtechniques described above to extract the nail from the section of therecycled wood workpiece 115.

In another implementation, the local controller 170 can calculate thetarget depth for the jaws 128 as a function of a diameter of the head ofthe nail, such as a target depth corresponding to a distance below thenail head equivalent to one diameter of the nail head derived from anX-ray or color image of the recycled wood workpiece 115 and less thanthe maximum jaw depth. Furthermore, the local controller 170 canimplement the methods and techniques described above for a straight andsubsurface nail to autonomously navigate the multi-axis stage 121 andthe gear to locate the set of jaws 128 adjacent (e.g., spanning) asegment of a non-threaded fastener extending below the adjacent surfaceof the recycled wood workpiece 115 based on the target depth of the setof jaws 128 and locate the retraction axis of the set of jaws 128coaxial with the axis of the nail.

For example, the local controller 170 can: calculate a diameter (e.g.,9/32 inches) of the head of the straight nail and a length (e.g., 2.5inches) of the shank of the straight nail; and calculate a target depth(e.g., 0.25 inches) of the jaws 128 to open and clear the head of thestraight nail and to plunge below the surface (e.g., extend into thesection) of the recycled wood workpiece 115 to clamp the shank of thestraight nail. The local controller 170 can then derive the target jawposition to align the retraction axis of the set of jaws 128 coaxialwith the shank axis of the straight nail; autonomously navigate themulti-axis stage 121, the yaw actuator 127, and the jaw actuator 125: toclamp the jaws 128 onto the shank of the straight nail, extending belowthe adjacent surface of the recycled wood workpiece 115, at the targetdepth (e.g., 0.25 inches) of the set of jaws 128; to locate theretraction axis of the set of jaws 128 coaxial with the axis of thestraight nail; and to extract the straight nail extending below thesurface of the recycled wood workpiece 115, along the shank axis, fromthe section of the recycled wood workpiece 115 (e.g., Y-axis of thenon-threaded fastener extractor module 120).

7.5.3 Superficial Bent Nail Removal Cycle

In one implementation, the local controller 170 can identify a bent nailsuperficial to a recycled wood workpiece 115 occupying the work volume109 (e.g., protruding above the surface of the of recycled woodworkpiece 115); derive a position and an orientation of a shank of thebent nail in the work volume 109; and derive a curvature of the shank(e.g., shaft, shank) of the bent nail, based on features extracted froman image of the recycled wood workpiece 115 captured by the opticalsensor 110.

In one variation, the local controller 170 can: identify an engagementpoint of the base of the shank of the bent nail entering the recycledwood workpiece 115; derive a shank axis of the bent nail relative therecycled wood workpiece 115 based on the engagement point; calculate atarget orientation for the set of jaws 128 based on the curvature of thebent nail; autonomously navigate the multi-axis stage 121 to align theretraction axis of the set of jaws 128 coaxial with the shank axis ofthe bent nail; trigger the yaw actuator 127 to rotate the set of jaws128 to the target orientation; trigger the jaw actuator 125 to close theset of jaws 128 against the bent nail with a target clamping force, atthe engagement point to extract the bent nail along the shank axis fromthe recycled wood workpiece 115; trigger the vertical stage 124 toretract the bearing plate 123; and trigger the jaw actuator 125 to openthe set of jaws 128 to release the bent nail into a fastener container145.

For example, the local controller 170 can: define a target engagementposition of the non-threaded fastener end effector 122, to engage theshank of the bent nail, based on the position and orientation of thebent nail within the work volume 109; derive a shank axis of the bentnail relative a longitudinal axis of the recycled wood workpiece 115based on the target engagement position; define a target jaw positionfor the set of jaws 128 based on the curvature of the bent nail; triggerthe stage to drive the non-threaded fastener end effector 122 to align aretraction axis of the set of jaws 128 coaxial with the shank axis ofthe bent nail; trigger the jaw actuator 127 to drive the set of jaws 128to engage the shank of the bent nail at the target jaw position; andtrigger the stage to retract the non-threaded fastener end effector 122from the target engagement position to extract the bent nail, along theshank axis, from the recycled wood workpiece 115.

7.5.4 Subsurface+Flush Bent Nail Removal Cycle

In one implementation, the local controller 170 can identify a bent nailextending below the surface of the recycled wood workpiece 115 (e.g.,subsurface) occupying the work volume 109 and derive a curvature of theshank (e.g., shaft, shank) of the bent nail below the surface of therecycled wood workpiece 115, based on an image of the recycled woodworkpiece 115 captured by the optical sensor 110.

Then, the local controller 170 can: access a maximum jaw depth forremoving a straight nail (e.g., 0.5 inches); and calculate a targetdepth of the jaws 128 to engage a shank of the bent nail below the nailhead, such as including plunging the jaws 128 below the surface of therecycled wood workpiece 115 to clamp against the shank of the nail at anengagement point. In particular, in this implementation, the localcontroller 170 can calculate the target depth for the jaws 128 as afunction of a total length of a straight segment of the shank of thenail, such as a target depth corresponding to a distance below the nailhead derived from an X-ray or color image of the recycled wood workpiece115 and less than the maximum jaw depth.

In one variation, the local controller 170 can identify an engagementpoint of the straight segment of the shank of the bent nail closest tothe surface of the recycled wood workpiece 115; and derive a shank axisof the bent nail relative the recycled wood workpiece 115 based on theengagement point. The local controller 170 can then implement themethods and techniques described above to close the set of jaws 128against the bent nail with a target clamping force, at the engagementpoint to extract the bent nail along the shank axis from the recycledwood workpiece 115.

In another variation, the local controller 170 can calculate a targetretraction axis of the bent nail based on the curvature of the bent nail(e.g., 20% of the curvature of the curved nail, 30% of the curvature ofthe curved nail) to locate a jaw axis of the jaws 128 perpendicular tothe recycled wood workpiece 115 (e.g., along the grain of the recycledwood workpiece 115) to reduce and/or eliminate accidental splitting ofthe recycled wood workpiece 115 during a bent nail removal cycle.Furthermore, the local controller 170 can calculate a target depth ofthe jaws 128 (e.g., 0.30 inches) to plunge below the surface of therecycled wood workpiece 115 and clamp the jaws 128 onto the shank of thebent nail. Then, the local controller 170 can autonomously navigate themulti-axis stage 121 and the yaw actuator 127: to locate the jaws 128adjacent (e.g., spanning) the curvature of the bent nail extending belowthe adjacent surface of the recycled wood workpiece 115 according to thetarget retraction axis of the jaws 128 and the target depth of the jaws128; and to locate the orientation of the jaws 128 coaxial with thepredicted orientation of the bent nail.

For example, the local controller 170 can: detect a bent nail embeddedin the section of the recycled wood workpiece 115 in the image; detect acurvature and a shank of the bent nail based on features extracted fromthe image of the work volume 109; calculate a target depth for the setof jaws 128 to extend into the section of the recycled wood workpiece115 to engage the bent nail at the engagement point, based on the shankof the bent nail; derive a shank axis of the bent nail relative thelongitudinal axis of the recycled wood workpiece 115 based on thecurvature of the bent nail; derive a target jaw position to align theretraction axis of the set of jaws 128 coaxial with the shank axis ofthe bent nail; and retract the threaded fastener end effector 132 toextract the bent nail, along the shank axis, from the section of therecycled wood workpiece 115.

Thus, the local controller 170 can trigger the jaw actuator 125 to closethe set of jaws 128 against the shank of a bent nail below the surfaceof the recycled wood workpiece 115, straighten the nail along theY-axis, and extract the nail along the Y-axis of the non-threadedfastener extractor module 120 for the bent nail with minimal to notorque applied to the set of jaws 128, thereby reducing and/oreliminating failure (e.g., slipping, snipping, missing, accidentalsplitting of the recycled wood workpiece 115) during the bent nailremoval cycle.

However, the local controller 170 can implement similar methods andtechniques to remove a bent nail flush with the surface of the recycledwood workpiece 115.

7.5.5 Staple+Retainer Nail Removal Cycle

Generally, the local controller 170 can implement the methods andtechniques described above to remove a staple, extending below and/orembedded within the surface of the recycled wood workpiece 115,according to a fastener removal schedule corresponding to a staple.

In one variation, the local controller 170 can access a table (e.g.,list, chart) of staple dimensions and a predefined dimension thresholdfor staples and access an image of the work volume 109 captured by theoptical sensor 110. Based on features extracted from the image, thelocal controller 170 can: detect a staple embedded in a surface of therecycled wood workpiece 115 occupying the work volume 109; derive adimension of the staple in the work volume 109; and detect a firstvertex (e.g., (x,y) position) of the staple defining a first height anda second vertex (e.g., (x,y) position) of the staple defining a secondheight less than the first height. Then, in response to the dimension ofthe staple falling below the threshold staple dimension, the localcontroller 170 can identify the staple as negligible (e.g., leave thestaple within the recycled wood workpiece 115) and move on to a nextnon-threaded fastener in the recycled wood workpiece 115. For example,the local controller 170 can access a table (e.g., list, chart) ofstaple dimensions and a predefined dimension threshold (e.g., 26/8 or 26mm crown and 8 mm legs) for staples. The local controller 170 can thenidentify the dimension of the staple (e.g., 24/6 or 24 mm crown and 6 mmlegs) based on a first leg, a crown, and a second leg—extending belowthe surface of the recycled wood workpiece 115—and, in response to thedimension of the staple falling below the threshold staple dimension(e.g., 26/8 or 26 mm crown and 8 mm legs), the local controller 170 canidentify the staple as negligible (e.g., leave the staple within therecycled wood workpiece 115) and move on to a next non-threaded fastenerin the recycled wood workpiece 115.

Alternatively, in response to the dimension of the staple exceeding thethreshold staple dimension, the local controller 170 can: derive avertical plane between the first vertex and the second vertex of thestaple based on the first height and the second height; define a targetjaw position to align the retraction axis of the set of jaws 128 of theset of jaws 128 parallel to the vertical plane between the first vertexand the second vertex of the staple; identify the first vertex within athreshold distance of the surface of the recycled wood workpiece 115(e.g., closest to the recycled wood workpiece 115 surface) based on thefirst height; derive a target depth for the set of jaws 128 to engagethe first vertex of the staple based on the first height; trigger thejaw actuator 125 to drive the set of jaws 128 to engage the first vertexof the staple to a target engagement position (e.g., (x,y) position) andthe target jaw position according to the target depth; and trigger thestage to retract the non-threaded fastener end effector 122 from thetarget engagement position to extract the staple, along the verticalplane (e.g., Y-axis of the non-threaded fastener extractor module 120),from the recycled wood workpiece 115.

For example, the local controller 170 can identify the next non-threadedfastener in the recycled wood workpiece 115 as a staple. Accordingly,the local controller 170 can identify the dimension of the staple (e.g.,28/10 or 28 mm crown and 10 mm legs) based on a first leg, a crown, anda second leg—extending below the surface of the recycled wood workpiece115—and, in response to the dimension of the staple exceeding thethreshold staple dimension (e.g., 26/8 or 26 mm crown and 8 mm legs),the local controller 170 can detect a first vertex (e.g., 4,3) of thestaple between a first point of the crown of the staple, a second pointof the crown of the staple, and a third point at a distal end of a firstleg of the staple, closest to the recycled wood workpiece 115 surfacerelative the extractor coordinate system of the non-threaded fastenerextractor module 120. The local controller 170 can also detect a secondvertex of the staple between the first point of the crown of the staple,the second point of the crown of the staple, and a fourth point at adistal end of a second leg of the staple. The local controller 170 canthen trigger the jaw actuator 125 to extend the jaws 128 to clamp thestaple at the first vertex (e.g., 4,3) and to extract the staple alongthe Y-axis of the non-threaded fastener extractor module 120.

The local controller 170 can implement the methods and techniquesdescribed above to remove a staple, extending below the surface of therecycled wood workpiece 115, according to a fastener removal schedulecorresponding to a staple. However, the local controller 170 can alsoimplement the methods and techniques described above to remove a nailretainer, extending below the surface of the recycled wood workpiece115, according to a fastener removal schedule corresponding to the nailretainer fastener.

7.6 Failures

Generally, the primary controller 160 (or the local controller 170 inthe non-threaded fastener extractor module 120) can detect failures inthe removal of non-threaded fasteners based on non-optical data capturedby sensors arranged on the non-threaded fastener extractor module 120and implement computer vision techniques to detect and distinguishcommon removal failures—such as slipped, snipped, missed, etc.—for eachtype of fastener (e.g., nail, screw, staple). The system 100 can thenreceive these common removal failures and update the fastener removalschedules to reduce failure of future non-threaded fasteners withanalogous characteristics such as fastener type, location relative arecycled wood workpiece 115 (e.g., subsurface, super surface, flush),and/or fastener size.

In one implementation, during a non-threaded fastener removal cycle, thelocal controller 170 can track an applied force of the jaw actuator 125and an offset distance between the set of jaws 128 based on sensorsarranged in the non-threaded fastener end effector 122. Then, inresponse to detecting absence of an offset distance between the set ofjaws 128 and in response to detecting a decrease in the applied force,the local controller 170 can: identify a snipped failure of the set ofjaws 128 on a non-threaded fastener; trigger the jaw actuator 125 torelease the set of jaws 128; update the target position, targetorientation, and target depth for removal of the non-threaded fastener;and drive the yaw actuator 127 and the jaw actuator 125 to recenter theset of jaws 128 on the non-threaded fastener for the removal cycle.

Alternatively, in response to detecting absence of an offset distancebetween the set of jaws 128 and in response to detecting an increase inthe applied force followed by a sharp decrease, the local controller 170can: identify a slipped failure of the set of jaws 128 on a non-threadedfastener; trigger the jaw actuator 125 to open the jaws 128; update thetarget position, target orientation, and applied force for removal ofthe non-threaded fastener; and drive the yaw actuator 127 to rotate thejaws 128 and the jaw actuator 125 to recenter the jaws 128 on thenon-threaded fastener for the removal cycle. The local controller 170can repeat the foregoing process until the non-threaded fastener isremoved from the recycled wood workpiece 115 and/or until an attemptthreshold is achieved (e.g., 2 attempts, 3 attempts). Additionally,responsive to the quantity of attempts (e.g., 3 attempts) exceeding theattempt threshold (e.g., 2 attempts), the local controller 170 canidentify the removal cycle as a miss failure and navigate the multi-axisstage 121 to locate the non-threaded fastener end effector 122 over thenext non-threaded fastener in the recycled wood workpiece 115.

7.7 Non-Threaded Fastener Realignment

In one variation, during a non-threaded fastener removal cycle, theprimary controller 160 (or the local controller 170 in the non-threadedfastener extractor module 120) can further: monitor load and/or back EMFon the set of actuators coupled to the multi-axis stage 121; monitorpositions of the multi-axis stage 121 and the linear stage; interpret anangular offset between the axis of the non-threaded fastener and theW-axis of the jaws 128 based on positional oscillations in thenon-threaded fastener extractor module 120 while the gear rotates thejaws 128; and then drive these to alternate positions to reduce thesepositional oscillations, improve alignment between the axis of thenon-threaded fastener and the W-axis of the jaws 128, and thus reducefatigue on the non-threaded fastener that may otherwise result infailure before complete removal of the non-threaded fastener from therecycled wood workpiece 115.

8. Threaded Fastener Extractor Module

As described above, the system 100 can include a set of threadedfastener extractor modules 130 for removing threaded fasteners embeddedwithin and/or extending above a recycled wood workpiece 115. Eachthreaded fastener extractor module 130 includes: a multi-axis stage 131;a threaded fastener end effector; a set of module actuators; and a localcontroller 170.

In one implementation, each threaded fastener extractor module 130 issupported and manipulated on the chassis 102 via the stage, defines arotational axis (e.g., R-axis), and includes: a ram 136 configured torotate about the rotational axis; a ram actuator 137 configured toactuate the ram 136; a set of jaws 139 coupled to the ram 136 andconfigured to engage and retain metal fasteners from the section of therecycled wood workpiece 115; and a jaw actuator 138 configured toactuate the set of jaws 139.

8.1 Gantry and Actuators

In one implementation, the multi-axis stage 131 includes a three-axisgantry: supported by the chassis 102; arranged in a work volume 109 overa section of the linear sled stage; configured to face (e.g., isarranged over, under, or adjacent) one side of a recycled wood workpiece115 loaded onto the sled; and configured to support the threadedfastener end effector over a range of vertical, lateral, andlongitudinal positions to enable the threaded fastener end effector toaccess screws in a range of positions and orientations on the adjacentside of the recycled wood workpiece 115.

In this implementation, the threaded fastener end effector can alsoinclude two perpendicular rotational stages (e.g., B- and C-axes)arranged on the distal end of the three-axis gantry (e.g., X-, Y-, andZ-axes).

The set of actuators can include a set of stepper or servo motorscoupled to and configured to independently actuate each axis of thestage, such as via a belt or leadscrew. Furthermore, the threadedfastener extractor module 130 can include a set of position sensors—suchas rotary or linear encoders coupled to the set of actuators or directlyto the stage, respectively. The local controller 170 can track theposition of each axis of the stage via these position sensors andinterpolate the three-dimensional position of the threaded fastener endeffector—mounted to the third axis of the gantry—within the work volume109 based on the combined positions of these axes of the stage.

For example, the three-axis gantry is arranged in the work volume 109and facing a first side of the recycled wood workpiece 115 loaded ontothe conveyor 105. A position sensor is mounted to the three-axis gantryand configured to output signals representing positions of thethree-axis gantry. In this example, the local controller 170 can then:interpret a set of positions of the three-axis gantry based on positionsof the three-axis gantry detected by the position sensor; andinterpolate a three-dimensional position—such as a surge position, aheave position, and a sway position (e.g., (x,y,z) position within thecoordinate system of the non-threaded fastener extractor module 120)—ofthe threaded fastener end effector within the work volume 109 based onthe set of positions.

In another implementation, the stage includes a robotic arm, such as athree-link robotic arm with base rigidly mounted to the chassis 102 andconfigured to reach the full length and width of the near side of asegment of a recycled wood workpiece 115 occupying the work volume 109.In this implementation, the set of actuators are configured tomanipulate joints between the base and links of the robotic arm.

In a similar implementation, the stage includes: a single-axis gantryarranged over (or adjacent, under) and parallel to the linear sledstage; and a two-link robotic arm mounted to the gantry and configuredto cooperate with the gantry to reach the full length and width of thenear side of a segment of a recycled wood workpiece 115 occupying thework volume 109. In this implementation, the set of actuators areconfigured to manipulate the gantry and joints between links of therobotic arm to reach the threaded fastener end effector throughout thescope of the work volume 109.

Furthermore, the threaded fastener extractor module 130 can include aset of position sensors—such as linear or rotary encoders—coupled tojoints of the robotic arm and/or to axes of the gantry. The localcontroller 170 can track the position of the distal end of the roboticarm—and therefore, the threaded fastener end effector—within the workvolume 109 based on the positions of joints of the robotic arm and theposition of the gantry within the work volume 109.

However, the multi-axis stage 131 can define any other configuration orarrangement of actuators and supporting structures.

8.2 Threaded Fastener End Effector

As described above, the threaded fastener end effector is supported bythe multi-axis stage 131 and includes: a housing 134; a ram 136 arrangedin the housing 134 and operable between an extended position and aretracted position to accommodate retraction of a threaded fastener froma recycled wood workpiece 115; a set of jaws 139 arranged on a distalend of the ram 136; a jaw actuator 138 configured to close the set ofjaws 139 against the threaded fastener; and a ram actuator 137configured to rotate the ram 136 in the housing 134.

8.2.1 Housing

In one implementation, the housing 134: is pivotably coupled to a distalend of the multi-axis stage 131; includes a set of bearing journalsconcentric with an R-axis of the threaded fastener end effector 132;defines a ram actuator 137 mount configured to support and locate theram actuator 137; and defines a jaw actuator 138 mount configured tosupport and locate the jaw actuator 138.

In one variation, the housing 134 is pivotably coupled to the stage andconfigured to support the ram 136. A spring 135 is arranged in thehousing 134 and is configured to advance the ram 136 to a maximumextension position and retract the ram 136 to a minimum extensionposition.

8.2.2 Ram

The ram 136: defines an internal bore configured to support a pushrod;is supported by and configured to rotate in the set of bearing journalsof the housing 134; and includes a mesh—such as a timing belt gear ortiming gear—configured to couple to the ram actuator 137. A distal endof the ram 136: defines a set of (e.g., two) jaw pivots; and/or definesa linear bearing configured to support a distal end of the pushrod.

8.2.3 Jaws

The threaded fastener extractor module 130 also includes a set of (e.g.,two, three) jaws 139, each: pivotably coupled to a jaw pivot at thedistal end of the ram 136 of each threaded fastener extractor module130. The set of jaws 139 are operable in: a closed position to clampagainst and retain a head and/or shank of a screw and to transfer atorque (e.g., retraction force)—applied to the ram 136 by the ramactuator 137—into the screw to retract the screw from a recycled woodworkpiece 115 during a screw removal cycle; and an open position torelease the screw, such as into a fastener container 145 followingcompletion of the screw removal cycle. For example, each jaw 139 caninclude a hardened steel jaw with serrated jaw surface configured toengage and retain a head or shank of a screw.

8.2.4 Pushrod and Jaw Actuator

The threaded fastener end effector can also include a pushrod: runninginside the ram 136; defining a distal end that runs in and is supportedby the linear bearing on the distal end of the ram 136; and coupled toeach jaw 139 via a connecting rod.

The jaw actuator 138 can include an electromechanical, pneumatic, orhydraulic linear actuator: mounted to the housing 134 aft of the ram136; and configured to advance and retract the pushrod within the ram136, thereby clamping and releasing the set of jaws 139 on a screw inthe closed and open positions, respectfully.

The threaded fastener extractor module 130 can also include: a thrustbearing—such as a captured spherical or tapered bearing—interposedbetween the proximal end of the pushrod and the jaw actuator 138 andconfigured to: transfer a linear force applied by the jaw actuator 138into the pushrod to open or close the jaws 139; and transmit no orminimal torque on the pushrod—such as applied by the ram actuator 137 ora screw—into the jaw actuator 138 of a threaded fastener extractormodule 130.

Therefore, at the start of a screw removal cycle, the local controller170 can: trigger the jaw actuator 138 to retract the jaws 139, therebyopening the jaws 139 to receive a next fastener; autonomously navigatethe threaded fastener end effector to a target position that the localcontroller 170 predicts contains a head and/or a shank of a screw; andtrigger the jaw actuator 138 to advance the pushrod forward and to applya target compressive force onto the proximal end of the pushrod, therebydriving the jaws 139 closed onto the screw and clamping the screw with atarget clamping force. Upon completion of the screw retraction cycle,the local controller 170 can trigger the jaw actuator 138 to retract thepushrod, thereby opening the jaws 139 and releasing the screw.

8.3 R-axis Home Position

In one implementation, the housing 134: is mounted to the distal end ofthe multi-axis stage 131 via a linear slide; and is operable over arange of linear positions on the linear slide parallel to the R-axis ofrotation of the ram 136 (e.g., rotational axis of the threaded fastenerend effector 132). In this implementation, the threaded fastener endeffector can also include a secondary housing 134 actuator: coupled tothe housing 134 or linear slide; configured to drive the housing 134—andtherefore the ram 136, the set of jaws 139, etc.—forward to a homeposition in preparation for engaging the jaws 139 against a next screw;and configured to release forward pressure on the housing 134 to enablethe housing 134 to retract from a nearby recycled wood workpiece 115 asrotation of the ram 136 extracts this screw from the recycled woodworkpiece 115.

For example, the secondary housing 134 actuator can include a pneumaticpiston coupled to a pressure reservoir and an exhaust via a set ofvalves. At the start of a screw removal cycle, the local controller 170:activates a first valve to supply pressurized air to the housing 134actuator, which drives the housing 134 forward on the linear slide tostop at maximum extension; triggers the jaw actuator 138 to close thejaws 139; and then closes the first valve and opens a second value toenable air in the housing 134 actuator to vent to ambient, therebyreducing or eliminating forward force on the ram 136. The localcontroller 170 can then activate the ram actuator 137 to rotate the ram136, the jaws 139, and the screw—the latter of which backs out of therecycled wood workpiece 115 and thus drives the housing 134 up thelinear slide.

The threaded fastener end effector can also include a linear encoder, aset of home switches, or other position sensor coupled to the housing134 or linear slide. During a screw removal cycle, the local controller170 can: track the position of the housing 134 on the linear slide viathe position sensor; detect extraction of a threaded fastener from arecycled wood workpiece 115 based on retraction of the housing 134 onthe linear slide as the ram actuator 137 rotates the ram 136; detectremoval of a threaded fastener (or failure of the screw) from a recycledwood workpiece 115 based on retraction of the housing 134 on the linearslide as the ram actuator 137 rotates the ram 136 followed by thehousing 134 reaching a static linear position on the linear slide (andbased on minimal or no load on the ram actuator 137); and/or detect jawslippage on a screw or inadvertent engagement of a non-threaded fastener(e.g., a nail, a staple) based on absence of retraction of the housing134 on the linear slide as the ram actuator 137 rotates the ram 136 andbased on high load on the ram actuator 137.

For example, the local controller 170 can: trigger the ram actuator 137to align the rotational axis of the threaded fastener end effectorcoaxial with the detected orientation of a non-threaded fastener;trigger the ram actuator 137 to rotate the ram 136 about the rotationalaxis of the threaded fastener end effector and the set of jaws 139 toretract the non-threaded fastener with the retraction force from thesection of the recycled wood workpiece 115; and trigger the stage toretract the threaded fastener end effector from the first targetengagement position to remove the threaded fastener from the section ofthe recycled wood workpiece 115.

8.4 Ram Actuator

The ram actuator 137: is mounted to the housing 134; is coupled to themesh on the ram 136, such as via a geartrain or timing belt; and isconfigured to rotate the ram 136 about the R-axis. For example, the ramactuator 137 can include an electromechanical, pneumatic, or hydraulicrotary actuator.

8.5 Threaded Fastener Extractor Module: Degrees of Freedom

As described above, the multi-axis stage 131 is operable in threedegrees of freedom to locate the threaded fastener end effector over arange of positions within the work volume 109. The threaded fastener endeffector is pivotably coupled to the distal end of the multi-axis gantryvia the two driven rotational axes—such as a two-axis gimble—operable intwo additional degrees of freedom. Accordingly, the local controller 170can drive the multi-axis stage 131 and these two driven rotational axes:to locate a rotational axis (e.g., the R-axis) of the ram 136 coaxialwith a threaded fastener inset in a section of recycled wood workpiece115 occupying the operation theater of the threaded fastener extractormodule 130; and to locate the jaws 139 adjacent (e.g., spanning) thehead or shank of the threaded fastener protruding above the adjacentface of the recycled wood workpiece 115.

The ram actuator 137 in the threaded fastener end effector is configuredto rotate the ram 136 about the R-axis and thus defines a further degreeof freedom of the threaded fastener end effector. Accordingly, the localcontroller 170 can actuate the ram actuator 137, thereby rotating theram 136 and the jaws 139 and retracting a threaded fastener clamped bythe jaws 139.

The jaw actuator 138 is coupled to the jaws 139 via a pushrod and thrustbearing, is configured to open and close the jaws 139 independently ofrotation of the ram 136 and jaws 139, and thus defines a further degreeof freedom of the threaded fastener end effector. Accordingly, the localcontroller 170 can actuate the jaw actuator 138 to clamp the jaws 139against a threaded fastener extending above an adjacent side of therecycled wood workpiece 115.

Furthermore, the threaded fastener end effector is coupled to the twodriven rotational axes (or to the multi-axis stage 131 more generally)via a linear slide operable over a range of linear positions parallel tothe R-axis of rotation of the ram 136. As described above, the linearslide can enable the ram 136 and housing 134 to retract from theadjacent side of a recycled wood workpiece 115 as the threaded fastenerend effector removes a threaded fastener from the recycled woodworkpiece 115. Accordingly, the linear slide can define a further degreeof freedom of the threaded fastener end effector.

Therefore, the multi-axis stage 131 can support and locate the twodriven rotational axes in three degrees of freedom. The two drivenrotational axes locate the linear slide in two additional rotationaldegrees of freedom. The linear slide locates the housing 134 in afurther translation degree of freedom. The housing 134 locates the ram136 in an additional rotational degree of freedom and the jaw actuator138 and pushrod in a further translational degree of freedom. Thus, thethreaded fastener end effector can support and locate the jaws 139 ineight degrees of freedom.

However, the threaded fastener end effector described above can bearranged in any other configuration to similarly support and locate thejaws 139 in eight degrees of freedom. For example: the multi-axis stage131 can support and locate the two driven rotational axes in threedegrees of freedom; the two driven rotational axes locate the housing134 in two additional rotational degrees of freedom; the housing 134locates the ram 136 in both a translational degree of freedom and arotational degree of freedom; and the ram 136 supports the jaw actuator138 and pushrod in a further translational degree of freedom. Therefore,in this example, the threaded fastener end effector can again supportand locate the jaws 139 in eight degrees of freedom.

8.6 Screw Removal Cycle

In one implementation, once a section of a recycled wood workpiece 115enters a work volume 109 of a threaded fastener extractor module 130,the local controller 170 calculates a position and predicted orientationof a screw—on the section of the recycled wood workpiece 115—within alocal coordinate system of the threaded fastener extractor module 130based on: the position of the screw within the coordinate system of thevirtual model; the predicted orientation of the screw, within thecoordinate system of the virtual model, derived from the virtual model;the position of the section of the recycled wood workpiece 115 within aglobal coordinate system of the system 100; and/or a known or storedposition of the local coordinate system of the threaded fastenerextractor module 130 relative to the global coordinate system. The localcontroller 170 also: triggers the jaw actuator 138 to open the jaws 139;and triggers the secondary housing 134 actuator to fully advance thelinear slide.

The local controller 170 then: interpolates the position of the jaws 139and the R-axis of the threaded fastener end effector 132 within thelocal coordinate system based on positions of the multi-axis stage 131,the two driven rotational axes, and the linear slide, etc.; andautonomously navigates the multi-axis stage 131 and the two drivenrotational axes to locate the jaws 139 adjacent (e.g., spanning) asegment of the screw extending above the adjacent surface of therecycled wood workpiece 115 and to locate the R-axis of the ram 136coaxial with the predicted orientation of the screw.

The local controller 170 then: triggers the jaw actuator 138 to closethe jaws 139, thereby clamping the jaws 139 onto the screw; triggers thesecondary housing 134 actuator to release the linear slide; and triggersthe ram actuator 137 to rotate the ram 136, thereby rotating andextracting the screw from the recycled wood workpiece 115.

Furthermore, during this screw removal cycle and as described above, thelocal controller 170 can: actuate the secondary housing 134 actuator tobias (or “preload”) the jaws 139 and the housing 134 away from therecycled wood workpiece 115 and thus maintain a continuous retractionforce on the screw; track the position of the housing 134 on the linearslide via the position sensor; track load on the ram actuator 137 (e.g.,based on current draw of the ram actuator 137 or by reading a torquesensor coupled to the ram actuator 137); verify extraction of the screwfrom the recycled wood workpiece 115 responsive to retraction of thehousing 134 up the linear slide as the ram actuator 137 rotates the ram136; and detect removal of the screw from the recycled wood workpiece115 (or failure of the screw) responsive to subsequent cessation orretraction of the housing 134 up the linear slide and a drop in load onthe ram actuator 137. Upon detecting removal (or failure) of the screw,the local controller 170 can: autonomously navigate the multi-axis stage131 and the two driven rotational axes to locate the jaws 139 over thewaste bin; trigger the jaw actuator 138 to open the jaws 139, therebyreleasing the screw into the waste bin; verify removal of the screw inresponse to detecting an object passing the break beam or motion sensoron the waste bin within a threshold duration (e.g., one second) aftertriggering the jaw actuator 138 to open the jaws 139; and record removalof the screw from the recycled wood workpiece 115, such as by annotatinga representation of the screw in the virtual model with a “removed”flag.

Furthermore, during a screw removal cycle, the primary controller 160(or the local controller 170 in the threaded fastener extractor module130) can: detect jaw slippage on a screw in response to detectingabsence of retraction of the housing 134 on the linear slide as the ramactuator 137 rotates the ram 136 when load on the ram actuator 137 ishigh; and then trigger the jaw actuator 138 to release the jaws 139,drive the set of actuators to recenter the jaws 139 on the screw, andthen repeat the foregoing process to remove the screw from the recycledwood workpiece 115.

In one implementation, the threaded fastener end effector 132 caninclude: a force sensor coupled to the threaded fastener end effector132 and configured to output a first signal representing retractionforce of the set of jaws 139 on a fastener during retraction of thefastener from the section of the recycled wood workpiece 115; and aposition sensor configured to output a second signal corresponding to aposition of the housing 134 on the stage. In this implementation, thelocal controller 170 can: interpret a first retraction force of the setof jaws 139 on the first fastener based on the first signal; interpret afirst position of the housing 134 based on the second signal; andconfirm extraction of the fastener from the section of the recycled woodworkpiece 115, in response to the first position of the housing 134falling within a first target position range and in response to thefirst retraction force of the set of jaws 139 falling below a retractionforce threshold.

Alternatively, the force sensor is configured to output a third signalrepresenting retraction force of the set of jaws 139 on the fastener andthe position sensor is configured to output a fourth signalcorresponding to the position of the housing 134 on the stage. The localcontroller 170 can then: interpret a second retraction force of the setof jaws 139 on the first fastener based on the third signal; interpret asecond position of the housing 134 based on the fourth signal; andidentify jaw slippage of the set of jaws 139 with the fastener in thesection of the recycled wood workpiece 115, in response to the secondposition of the housing 134 falling within a second target positionrange less than the first target position range and in response to thesecond retraction force of the set of jaws 139 falling below theretraction force threshold.

The threaded fastener extractor module 130 can repeat this process foreach other screw detected on the adjacent side of the recycled woodworkpiece 115 occupying the work volume 109.

8.6.1 Superficial Screw Removal

In one implementation, the local controller 170 can identify a screwnon-normal to the surface of a recycled wood workpiece 115 occupying thework volume 109 and superficial to the recycled wood workpiece 115(e.g., protruding above the surface of the of recycled wood workpiece115) based on an image of the work volume 109 captured by the opticalsensor 110.

For example, the local controller 170 can: access the virtual model(e.g., three-dimensional model) of the work volume 109 occupied by therecycled wood workpiece 115 labeled with fastener types, positions, andorientations; scan the virtual model for the fastener; and identify thefastener in the virtual model labeled with a screw fastener type basedon the position and the orientation of the shank of the fastener; accessan image of the work volume 109 occupied by the section of the recycledwood workpiece 115 and extract a set of features from the image. Then,based on the set of features in the image, the local controller 170 can:detect a screw superficial to a surface of the recycled wood workpiece115 occupying the work volume 109; and derive a position, anorientation, and a length of a shank of the screw in the work volume109. The local controller 170 can then: define a target torque of theram actuator 137, to rotate the ram 136 and the set of jaws 139 aboutthe rotational axis of the threaded fastener end effector 132 to retractthe screw, based on the length of the shank of the screw; define a shankaxis of the screw relative a longitudinal axis of the recycled woodworkpiece 115 based on the orientation of the shank of the screw; definea target engagement position of the threaded fastener end effector 132,to engage the screw, based on the position of the shank of the screw;trigger the stage to drive the threaded fastener end effector 132 to thetarget engagement position; trigger the ram actuator 137 to align therotational axis of the threaded fastener end effector 132 coaxial withthe shank axis of the shank of the screw; trigger the jaw actuator 138to drive the set of jaws 139 to engage the shank of the screw in thesection of the recycled wood workpiece 115 at the target engagementposition; trigger the ram actuator 137 to rotate the ram 136 and the setof jaws 139 according to the target torque, to retract the screw, alongthe shank axis, from the section of the recycled wood workpiece 115; andtrigger the stage to retract the threaded fastener end effector 132 fromthe target engagement position to remove the screw from the recycledwood workpiece 115.

8.6.2 Subsurface+Flush Screw Removal

In one implementation, the local controller 170 can identify a screwembedded within the surface and/or extending below the surface (e.g.,subsurface) of a recycled wood workpiece 115 occupying the work volume109 and flush to the recycled wood workpiece 115 based on an image ofthe work volume 109 captured by the optical sensor 110. In thisimplementation, the local controller 170 can implement methods andtechniques described above to trigger the threaded fastener end effector132 to engage a head of the screw for removal from the recycled woodworkpiece 115.

For example, the local controller 170 can: derive a position andorientation of a head of the screw in the work volume 109 based on theset of features; define a shank axis of the screw relative alongitudinal axis of the recycled wood workpiece 115 based on theorientation of the head of the screw; define a target engagementposition of the threaded fastener end effector 132, to engage the screw,based on the position of the head of the screw; trigger the stage todrive the threaded fastener end effector 132 to the target engagementposition; trigger the ram actuator 137 to locate the rotational axis ofthe threaded fastener end effector 132 coaxial with the shank axis ofthe head of the screw; trigger the jaw actuator 138 to drive the set ofjaws 139 to engage the head of the screw in the section of the recycledwood workpiece 115 at the target engagement position; trigger the ramactuator 137 to rotate the ram 136 and the set of jaws 139 to retractthe screw, along the shank axis, from the section of the recycled woodworkpiece 115; and trigger the stage to retract the threaded fastenerend effector 132 from the target engagement position to remove the screwfrom the recycled wood workpiece 115.

8.7 Threaded Fastener Realignment

In one variation, during a screw removal cycle, the primary controller160 (or the local controller 170 in the threaded fastener extractormodule 130) can further: monitor torque (or load, back EMF) on the setof actuators coupled to the multi-axis stage 131, the two drivenrotational axes, and the ram actuator 137; monitor positions of themulti-axis stage 131, the two driven rotational axes, and the linearslide; interpret an angular offset between the axis of the screw and theR-axis of the ram 136 based on torque and/or positional oscillations inthe threaded fastener extractor module 130 while the ram actuator 137rotates the ram 136; and then drives these to alternate positions toreduce these torque and/or positional oscillations, improve alignmentbetween the axis of the screw and the R-axis of the ram 136, and thusreduce fatigue on the screw that may otherwise result in screw failurebefore the threaded fastener extractor module 130 fully removes thescrew from the recycled wood workpiece 115.

For example, the local controller 170 can implement closed-loop controlsto: serially oscillate each of the driven rotational axes and each axisof the multi-axis stage 131, such as over narrow angular or linearposition windows; and update a target position of each axis of thethreaded fastener extractor module 130 to positions that yield minimumand/or most consistent torque outputs on each stage as the ram actuator137 rotates the ram 136 to extract the screw during the screw removalcycle.

In another example, the local controller 170 can track oscillation ofaxes within the threaded fastener extractor module 130 during a firstrotation of the ram 136 during the screw removal cycle. In this example,the local controller 170 can then: pause rotation of the ram 136;trigger the jaw actuator 138 to release the jaws 139 from the screw;implement a threaded fastener extractor module 130 model to calculate anoffset between the axis of the screw and the R-axis of the ram 136 basedon the verified position of the screw and oscillation of each axis ofthe threaded fastener extractor module 130 during the first rotation ram136; drive actuators in the threaded fastener extractor module 130 toreduce this offset; trigger the jaw actuator 138 to close the jaws 139onto the screw; and resume the screw removal cycle.

Alternatively, the local controller 170 can: track oscillation of axeswithin the threaded fastener extractor module 130 during a firstrotation of the ram 136 during the screw removal cycle; pause rotationof the ram 136; trigger the jaw actuator 138 to release the jaws 139from the screw; characterize the range of oscillation of each axis ofthe threaded fastener extractor module 130; move each axis of thethreaded fastener extractor module 130 to the center position within itscorresponding range of oscillations during the first rotation of the ram136; trigger the jaw actuator 138 to close the jaws 139 onto the screw;and then resume the screw removal cycle.

In yet another example, the local controller 170 can trigger the ramactuator 137 to rotate the ram 136 and the set of jaws 139 about therotational axis of the threaded fastener end effector 132 to retract thescrew from the section of the recycled wood workpiece 115 at a firsttime. The local controller 170 can then: record a retraction force ofthe set of jaws 139, via a force sensor arranged on the set of jaws 139,at the first time; retract the threaded fastener end effector 132 from atarget engagement position to remove the screw from the section of therecycled wood workpiece 115 at a second time succeeding the first time;record a position of the threaded fastener end effector 132, via aposition sensor arranged on the threaded fastener end effector 132, atthe second time; and, in response to the retraction force of the set ofjaws 139 falling below a retraction force threshold and in response tothe position of the threaded fastener end effector 132 falling within atarget position range, identify removal of the fastener from the sectionof the recycled wood workpiece 115 at the second time.

The systems and methods described herein can be embodied and/orimplemented at least in part as a machine configured to receive acomputer-readable medium storing computer-readable instructions. Theinstructions can be executed by computer-executable componentsintegrated with the application, applet, host, server, network, website,communication service, communication interface,hardware/firmware/software elements of a user computer or mobile device,wristband, smartphone, or any suitable combination thereof. Othersystems and methods of the embodiment can be embodied and/or implementedat least in part as a machine configured to receive a computer-readablemedium storing computer-readable instructions. The instructions can beexecuted by computer-executable components integrated bycomputer-executable components integrated with apparatuses and networksof the type described above. The computer-readable medium can be storedon any suitable computer readable media such as RAM 136s, ROMs, flashmemory, EEPROMs, optical devices (CD or DVD), hard drives, floppydrives, or any suitable device. The computer-executable component can bea processor but any suitable dedicated hardware device can(alternatively or additionally) execute the instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the embodiments of the invention without departing fromthe scope of this invention as defined in the following claims.

I claim:
 1. A system for extracting fasteners from a recycled woodworkpiece comprising: a chassis defining a work volume; a conveyor:configured to receive the recycled wood workpiece populated with metalfasteners; and configured to constrain a section of the recycled woodworkpiece within the work volume; an optical sensor facing the workvolume; a threaded fastener extractor module comprising: a stagesupported by the chassis; and a threaded fastener end effector:supported and manipulated on the chassis via the stage; defining arotational axis; and comprising: a ram configured to rotate about therotational axis; a ram actuator configured to actuate the ram; a set ofjaws coupled to the ram and configured to engage and retain metalfasteners from the section of the recycled wood workpiece; and a jawactuator configured to actuate the set of jaws; and a controllerconfigured to: access an image of the work volume captured by theoptical sensor; based on a set of features detected in the image: detecta first fastener in the section of the recycled wood workpiece occupyingthe work volume; and derive a first position and a first orientation ofthe first fastener in the work volume; define a first target engagementposition of the threaded fastener end effector, to engage the firstfastener, based on the first position and the first orientation of thefirst fastener in the work volume; trigger the stage to drive thethreaded fastener end effector to the first target engagement position;trigger the jaw actuator to drive the set of jaws to engage the firstfastener in the section of the recycled wood workpiece; and trigger theram actuator to rotate the ram and the set of jaws about the rotationalaxis of the threaded fastener end effector to retract the first fastenerfrom the section of the recycled wood workpiece.
 2. The system of claim1: wherein each jaw in the set of jaws: comprises a serrated jaw surfaceconfigured to engage and retain metal fasteners from the section of therecycled wood workpiece; and configured to transfer a retraction forcefrom the ram into metal fasteners from the section of the recycled woodworkpiece; and wherein the controller is further configured to: triggerthe ram actuator to align the rotational axis of the threaded fastenerend effector coaxial with the first orientation of the first fastener;trigger the ram actuator to rotate the ram about the rotational axis ofthe threaded fastener end effector and the set of jaws to retract thefirst fastener with the retraction force from the section of therecycled wood workpiece; and trigger the stage to retract the threadedfastener end effector from the first target engagement position toremove the first fastener from the section of the recycled woodworkpiece.
 3. The system of claim 1, wherein the controller is furtherconfigured to: based on the set of features in the image: detect thefirst fastener comprising a screw superficial to a surface of therecycled wood workpiece occupying the work volume; and derive a secondposition, a second orientation, and a length of a shank of the screw inthe work volume; define a target torque of the ram actuator, to rotatethe ram and the set of jaws about the rotational axis of the threadedfastener end effector to retract the screw, based on the length of theshank of the screw; define a normal axis of the screw relative alongitudinal axis of the recycled wood workpiece based on the secondorientation of the shank of the screw; define a second target engagementposition of the threaded fastener end effector, to engage the screw,based on the second position of the shank of the screw; trigger thestage to drive the threaded fastener end effector to the second targetengagement position; trigger the ram actuator to align the rotationalaxis of the threaded fastener end effector coaxial with the normal axisof the shank of the screw; trigger the jaw actuator to drive the set ofjaws to engage the shank of the screw in the section of the recycledwood workpiece at the second target engagement position; trigger the ramactuator to rotate the ram and the set of jaws according to the targettorque, to retract the screw, along the normal axis, from the section ofthe recycled wood workpiece; and trigger the stage to retract thethreaded fastener end effector from the second target engagementposition to remove the screw from the recycled wood workpiece.
 4. Thesystem of claim 1: further comprising a force sensor coupled to thethreaded fastener end effector and configured to output a first signalrepresenting retraction force of the set of jaws on the first fastenerduring retraction of the first fastener from the section of the recycledwood workpiece; wherein the threaded fastener end effector furthercomprises: a housing pivotably coupled to the stage and configured tosupport the ram; and a position sensor configured to output a secondsignal corresponding to a position of the housing on the stage; andwherein the controller is configured to: interpret a first retractionforce of the set of jaws on the first fastener based on the firstsignal; interpret a first position of the housing based on the secondsignal; and confirm extraction of the first fastener from the section ofthe recycled wood workpiece, in response to the first position of thehousing falling within a first target position range and in response tothe first retraction force of the set of jaws falling below a retractionforce threshold.
 5. The system of claim 4: wherein the force sensor isconfigured to output a third signal representing retraction force of theset of jaws on the first fastener; wherein the position sensor isconfigured to output a fourth signal corresponding to the position ofthe housing on the stage; and wherein the controller is configured to:interpret a second retraction force of the set of jaws on the firstfastener based on the third signal; interpret a second position of thehousing based on the fourth signal; and identify jaw slippage of the setof jaws with the first fastener in the section of the recycled woodworkpiece, in response to the second position of the housing fallingwithin a second target position range less than the first targetposition range and in response to the second retraction force of the setof jaws falling below the retraction force threshold.
 6. The system ofclaim 1: further comprising a fastener container: arranged below thechassis; defining an aperture; and configured to store extractedfasteners from the recycled wood workpiece; further comprising a breakbeam sensor: coupled to the fastener container; and configured to outputa signal corresponding to motion across the aperture; and wherein thecontroller is configured to: trigger the jaw actuator to disengage theset of jaws to release the first fastener into the fastener container;and confirm extraction of the first fastener into the fastener containerin response to the break beam sensor indicating motion across theaperture within a threshold duration of release of the set of jaws bythe jaw actuator.
 7. The system of claim 1: further comprising an X-raymodule defining a scan volume and comprising an X-ray sensor facing thescan volume; wherein the conveyor is configured to drive the recycledwood workpiece through the scan volume of the X-ray module; and whereinthe controller is configured to: access an X-ray scan of the recycledwood workpiece occupying the scan volume; detect a set of metalfasteners populated in the recycled wood workpiece; detect a firsthelical ridge fastener in the set of metal fasteners based on a secondset of features detected in the X-ray scan; extract an initial positionand an initial orientation of the first helical ridge fastener in theset of metal fasteners; correlate the second set of featuresrepresenting the first helical ridge fastener with known features ofthreaded fasteners from a threaded fastener database; compilecorrelations into a three-dimensional model of the work volume; labelthe first helical ridge fastener in the three-dimensional model with athreaded fastener type, the initial position, and the initialorientation; and identify the first fastener as the first helical ridgefastener in response to the first position and the first orientation ofthe first fastener matching the initial position and the initialorientation of the first helical ridge fastener.
 8. The system of claim7, wherein the controller is configured to: isolate a subsection in thethree-dimensional model containing the threaded fastener label; isolatea secondary subsection of the recycled wood workpiece in the imagecorresponding to the subsection in the three-dimensional model; extracta subset of features from a region in the image depicting the secondarysubsection of the recycled wood workpiece in the image; identify thesubset of features as a head of the first fastener; and map the initialposition and initial orientation of the first helical ridge fastenerfrom the subsection of the three-dimensional model to the first fastenerhead identified in the image.
 9. The system of claim 1: wherein thestage comprises a three-axis gantry: arranged in the work volume; andfacing a first side of the recycled wood workpiece loaded onto theconveyor; further comprising, a position sensor configured to outputsignals representing positions of the three-axis gantry; and wherein thecontroller is configured to: interpret a set of positions of thethree-axis gantry based on positions of the three-axis gantry detectedby the position sensor; and interpolate a three-dimensional position ofthe threaded fastener end effector within the work volume based on theset of positions, the three-dimensional position of the threadedfastener end effector comprising a surge position, a heave position, anda sway position.
 10. The system of claim 1, wherein the controller isfurther configured to: based on the set of features detected in theimage: detect the first fastener comprising a screw proud to a surfaceof the recycled wood workpiece occupying the work volume; and derive asecond position, a second orientation of a head of the screw in the workvolume; and define a normal axis of the screw relative a longitudinalaxis of the recycled wood workpiece based on the second orientation ofthe head of the screw; define a second target engagement position of thethreaded fastener end effector, to engage the screw, based on the secondposition of the head of the screw; trigger the stage to drive thethreaded fastener end effector to the second target engagement position;trigger the ram actuator to locate the rotational axis of the threadedfastener end effector coaxial with the normal axis of the head of thescrew; trigger the jaw actuator to drive the set of jaws to engage thehead of the screw in the section of the recycled wood workpiece at thesecond target engagement position; trigger the ram actuator to rotatethe ram and the set of jaws to retract the screw, along the normal axis,from the section of the recycled wood workpiece; and trigger the stageto retract the threaded fastener end effector from the second targetengagement position to remove the screw from the recycled woodworkpiece.
 11. The system of claim 1, wherein the chassis furthercomprises: a set of lateral clamps configured to constrain lateral sidesof the recycled wood workpiece at an input side of the chassis; and aset of vertical clamps configured to constrain vertical sides of therecycled wood workpiece at the input side of the chassis.
 12. The systemof claim 1, wherein the conveyor comprises: an input roller: coupled toan input side of a lateral axis of the threaded fastener extractormodule; and comprising a first set of standoffs: extending radially fromthe input roller; defining a length greater than a nominal fastenerlength; and configured to locate the recycled wood workpiece at theinput side; and an output roller: coupled to an output side of thelateral axis of the threaded fastener extractor module; and comprising asecond set of standoffs: extending radially from the output roller;defining the length greater than the nominal fastener length; andconfigured to locate the recycled wood workpiece at the output side. 13.The system of claim 1: wherein the threaded fastener end effector facesa first side of the section of the recycled wood workpiece within thework volume; wherein the first set of jaws are configured to engage andretain metal fasteners from the first side of the section of therecycled wood workpiece; and further comprising: a second stagesupported by the chassis; and a second threaded fastener end effector:facing a second side orthogonal to the first side of the section of therecycled wood workpiece within the work volume; defining a secondrotational axis; supported and manipulated on the chassis via the secondstage; and comprising: a second ram configured to rotate about thesecond rotational axis of the second threaded end effector; a second ramactuator configured to actuate the second ram; a second set of jawscoupled to the second ram and configured to engage and retract metalfasteners from the second side of the section of the recycled woodworkpiece; and a second jaw actuator configured to actuate the secondset of jaws.
 14. The system of claim 13, wherein the controller isfurther configured to: access a second image of the work volume capturedby the optical sensor; based on a second set of features detected in thesecond image: detect a second fastener in the second side of the sectionof the recycled wood workpiece occupying the work volume; and derive asecond position and a second orientation of the second fastener in thework volume; define a second target engagement position of the secondthreaded fastener end effector, to engage the second fastener, based onthe second position and the second orientation of the second fastenerwithin the work volume; derive an extraction order for the first stageand the second stage based on the first engagement position and thesecond engagement position; trigger the second stage to drive the secondthreaded fastener end effector to the second target engagement positionaccording to the extraction order; trigger the second jaw actuator todrive the second set of jaws to engage the second fastener in the secondside of the section of the recycled wood workpiece; and trigger thesecond ram actuator to rotate the second ram and the second set of jawsabout the second rotational axis of the second threaded fastener endeffector to retract the second fastener from the second side of thesection of the recycled wood workpiece.
 15. A system for removingfasteners from a recycled wood workpiece comprising: a chassis: defininga work volume; comprising a set of lateral clamps configured toconstrain lateral sides of the recycled wood workpiece at an input sideof the chassis; and comprising a set of vertical clamps configured toconstrain vertical sides of the recycled wood workpiece at the inputside of the chassis; a conveyor: configured to receive the recycled woodworkpiece populated with metal fasteners; and configured to constrain asection of the recycled wood workpiece within the work volume; anoptical sensor facing the work volume; and a threaded fastener extractormodule comprising: a stage supported by the chassis; and a threadedfastener end effector: supported and manipulated on the chassis via thestage; defining a rotational axis; and comprising: a ram configured torotate about the rotational axis; a ram actuator configured to actuatethe ram; a set of jaws coupled to the ram and configured to engage andretract metal fasteners from the section of the recycled wood workpiece;and a jaw actuator configured to open the set of jaws at a first heightand to close the set of jaws to engage fasteners from the section of therecycled wood workpiece at a second height less than the first height.16. A method for removing fasteners from a recycled wood workpiececomprising: receiving a section of the recycled wood workpiece within awork volume; accessing an image of the work volume, the image recordedby an optical sensor facing the work volume; extracting a set offeatures representing the section of the recycled wood workpiece fromthe image; based on the set of features: detecting a fastener embeddedin the section of the recycled wood workpiece; and deriving a positionand an orientation of a shank of the fastener; deriving a first targetengagement position of a threaded fastener end effector, to engage thefastener, based on the position of the shank of the fastener; and inresponse to driving the threaded fastener end effector to the firsttarget engagement position: locating the set of jaws within a thresholddistance of the section of the recycled wood workpiece and spanning theshank of the fastener; driving the threaded fastener end effector tolocate a rotational axis of the threaded fastener end effector coaxialwith the orientation of the shank of the fastener; triggering a jawactuator to drive the set of jaws into the section of the recycled woodworkpiece and close the set of jaws to engage the shank of the fastener;and triggering a ram actuator to rotate the ram and the set of jawsabout the rotational axis of the threaded fastener end effector toretract the first fastener from the section of the recycled woodworkpiece.
 17. The method of claim 16: wherein extracting theorientation of the shank of the fastener comprises extracting a breadthof the shank of the fastener based on the set of features; furthercomprising calculating a centroid of the shank of the fastener based onthe breadth; wherein driving the threaded fastener end effectorcomprises driving the threaded fastener end effector to align therotational axis of the threaded fastener end effector coaxial with thecentroid of the shank of the fastener; and further comprising triggeringthe jaw actuator to open the set of jaws by a distance proportional tothe breadth of the shank of the fastener, in response to driving thethreaded fastener end effector to the first target engagement position.18. The method of claim 16: further comprising: accessing athree-dimensional model of the work volume occupied by the recycled woodworkpiece labeled with fastener types, positions, and orientations;scanning the three-dimensional model for the fastener; and identifyingthe fastener in the three-dimensional model labeled with a screwfastener type based on the position and the orientation of the shank ofthe fastener; wherein detecting the fastener comprises detecting a screwembedded in the section of the recycled wood workpiece in the image;wherein extracting the orientation of the shank of the fastenercomprises extracting the orientation of the shank of the screw; andwherein triggering the ram actuator comprises triggering the ramactuator to rotate the ram and the set of jaws about the rotational axisof the threaded fastener end effector to retract the screw from thesection of the recycled wood workpiece.
 19. The method of claim 16:wherein triggering the ram actuator comprises triggering the ramactuator to rotate the ram and the set of jaws about the rotational axisof the threaded fastener end effector to retract the fastener from thesection of the recycled wood workpiece at a first time; and furthercomprising: recording a retraction force of the set of jaws, via a forcesensor arranged on the set of jaws, at the first time; retracting thethreaded fastener end effector from the first target engagement positionto remove the first fastener from the section of the recycled woodworkpiece at a second time succeeding the first time; recording aposition of the threaded fastener end effector, via a position sensorarranged on the threaded fastener end effector, at the second time; andin response to the retraction force of the set of jaws falling below aretraction force threshold and in response to the position of thethreaded fastener end effector falling within a target position range,identifying removal of the fastener from the section of the recycledwood workpiece at the second time.
 20. The method of claim 16: furthercomprising defining a normal axis of the fastener relative alongitudinal axis of the section of the recycled wood workpiece based onthe orientation of the shank of the fastener; and wherein driving thethreaded fastener end effector comprises driving the threaded fastenerend effector to locate the rotational axis of the threaded fastener endeffector coaxial with the normal axis of the fastener, in response todriving the threaded fastener end effector to the first targetengagement position.